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CycLOP.i!DiA OF Mechanics.— Cover 2 ] 



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Face Cover 2.] 



WHOLESALE 



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Face Half-Title.] 



CASSELL'S 

CYCLOPEDIA OF MECHANICS 




Cornell University 
Library 



The original of this book is in 
the Cornell University Library. 

There are no known copyright restrictions in 
the United States on the use of the text. 



http://www.archive.org/details/cu31924021892413 



CAS8ELLS 



CYCLOEIDIA OF MECHANICS 



CONTAINING 



' RECEIPTS, PROCESSES AND MEMORANDA FOR 

WORKSHOP USE 

« 

I BASED OK PERSONAL EXPERIENCE AND EXPERT KNOWLEDGE 

, WITH 1,200 ILLUSTRATIONS AND AN INDEX OF 8,500 ITEMS 



EDITED BY 

Paul N. Hasluck 

EDITOE OP "WOKK" AND "BUILDING WORLD," AUTHOE OF " HANDYBOOKS FOR HANDICRAFTS/" ETC. ETO. 



FIRST SERIES 



OASSELL AiTD COMPAJSTY, Limited 

LONBON, PARIS, NEW YORK k MELBOURNE 

1901 
ALL EIGHTS RESERVED 



A« \■\[,'£'i^ 




First Edition September 1900. 
Keprinied 1901. 



PREFACE. 

pASSELL'S, CYCLOPEDIA OF MECHANICS contains in a form convenient 
for ready reference and everyday use receipts, processes, and memoranda 
,^elected from a rich store of choice information contributed by a staff of 
skilful and talented technicians, upon whose practical experience and expert know- 
ledge the information is based. The matter contained in this volume has been 
carefuUy digested, freely illustrated, and made plain to those inexperienced. 

All compilations of receipts and memoranda for the use of mechanics that have 
been published — and some have atta,ined great popularity — differ from the present 
work in the important fact that every item in this volume is the paid contribution 
of an expert, written specially to satisfy the want of an inquirer, and each has 
challenged enlendation from a wide , circle of practical men. Corrective and 
supplementary matter supplied by these critical readers has been incorporated to 
ensure the greater efficiency of this work. 

A superficial glance through the pages of this volume might tend to a false 
impression that the varied coAtents are not readily available for easy and systematic 
reference. However, this is not so. Experience has shown that it is not possible 
to classify paragraphs that often include matters essentially different so that there 
shall be a definite place for every item, and the impossibility of such a course 
is particularly emphasised in the present collection, which embraces subjects widely 
diversified. Even a little consideration of this Cyclopsedia would show that no 
possible arrangement of the paragraphs would place them go that the several facts 
contained in each could be found with ease and certainty. The copious index 
provides a means by which every separate particular and detail of any kind dealt 
with in the volume may be traced and referred to with the least amount of 
trouble. This index also brings together every reference to the same subject, 
however widely they may be scattered, and all varied notes included under one 
heading are properly analysed and, thus disclosed, regrouped with kindred topics. 
No pains have been spared in the compilation of this index, which efficiently serves 



6 Cyclopaedia of Mechanics. 

a purpose impossible to be met by any arrangement of paragraphs comprising the 
volume. 

Amongst the items embodied in this work probably every reader can find 
some that contain information already known to him. Possibly some readers may 
be able to supplement the particulars given in respect of matters with which they 
are familiar. Any authentic supplementary particulars that are likely to be of 
benefit and that would increase the usefulness of the information will be welcomed, 
^nd should be sent to the undersigned, with the view to including them in a 
second volume, now in preparation, that will be issued when ready. 

Additional information or instruction on special details of the matters dealt 

with in Cassell's Cyclopedia of Mechanics may be obtained by addressing 

a question to Work or Building World, from the contents of which journals 

this Cycloptedia has been compiled, so that it may be submitted to the staff of 

contributors and answered in the columns of one of those journals in the usual 

course. 

P. N. HASLUCK 
La Belle Sauvage, 
London. 

September, 1900. 



INDEX TO ILLUSTRATIONS. 



(TTie Contents Indeyi is on pp. 355-383.) 



Acetylene Gas Generator, 282 
• for Magic Luutern^ 

67 
Aerated Water Machinej 329 
Alrer for Towels, 179 
Air-gun Construction, 256 
Air-pump for Blowlamp, 73 
Alarm, Electric, for Shop Door, 

181 
Aitar, Private, 106 
American Organ Reed-hook, , 299 
Roll-top Desk, Roll-shutter 

for,'. 291 

■ Angler's Three-legged Folding 

Stool, 21 
Antlers, Method of Mounting, 77 
Apple-scoop, Bonb, 47 
Aquarium Top, Pattern for, 118 
Ai'hour, 147 

Arc, Determining Centre of, 172 
-T — , Drawing, when Centre is 
inaccessible, 177 

' Lamp, Hand Feed, 344 

, Method of Developing, 227 

Arch, Brick, 278 

, , Centering for, 155 

, , Circle-on-circle, Centre for, 

171 

, Elliptic, 201, 211 

— , , Gothic, 196 

— -, Gauged, 285 

, Mouldings on, 146 , 

, Return Bead round, 158 

, Semi-elliptic, 209 , 

Architects' Perspective Draw- 
ings, 138 
^ Armcliair, Spring Seat of, 830 

■ Assembly-room Floor Joists, 217 
Automatic Sewage Filter, 203- 
Axle Boxes, Machine for with- 
drawing from Wheels, 126 

Baby's Cradle, Stand for, 41 

Swing; 205 

Bag Changing Box for Camera, 343 

Baiter's Steam-heated Oven, 37 

Balanced Steps, 177 

Ball, Cutting, Inside Ball, 325 

Bamboo, Bedstead, 46 

Cabinet, 132 

Camera Stand, 836 

Newspaper-jaok, 128, 134 

Rocking CI air, 237 

Table "Top, Method of fasten- 
ing Legs to, 128 

Band-saw Brazing, 272 

Wheel, Method of Fixing 

Leather to, 262 

Bands, Straw, 'Twisting Hook for, 
309 

Ban;o Worm Screws, 115 

Barber's Chair, 98 

Bam, Dutch, 182 

BaiTow, Child's, 216 

, Wheel, 176 

, - — , Frame of, 32 

Basket Repairing, 309 

Baskets for Single-sticks, 308 

Bath for Ferrotype Photography, 
307 

Bathroom Mirror, 186 

Bead round Arch, 158 

Beading St)indl^ for Lathe, 288 

Beadwork, fCabinet or Workbox 
for, 49 

Beam, Flitched, Section of, 162 

Beam-compasses, 321 

Bed-rest for Invalid, 139 

Bedroom Tahle, 36 

Bedstead, Bamboo, 46 

, Child's Wooden, 70 

, Curtain Rails. 104 

, Doll's Woiideh, 70 

, Wood Tester, Head for, 198 

, Wooden, 273 

Bellows, Conical, for Camera, 276 

Belts, Leather, Diagram of 

Power Ti'ansmission by, 99 

, Tent Pole Rack for, 260 

Bench, Circular Saw, 285 



Bending Block for Shackles, 67 

Brass Tubes, 316 

, Machine for, 286, 

316 
Bevel Set-square, Carpenter's, 160 
Bevelled Stock Hoops, 262 
Bevelling Frames, Apparatus for, 
270 

Glass, Wheels for, 314 

Bevels for Hips to Semi-octag- 
onal Lantern Light, 193 

Oval Cask Joints, 66 

Rafters, 57, 165 -■ 

Bier Stand for Mortuary, 73 
Billiard Table Corner, 158 
Bin for Poultry Food, 130 
Bird Cage, 169 

Room, Warming, 202 

Birds, Breeding Cage for, 228 
Blind, Wire, Frame for, 64 
I Block for Supporting Person on 
Cycle, 387 ' 

Blocks, Floor, Apparatus for 

Cutting, 330 ' 
Blowing Fan for Forge, 319 
Blow-lamp, Paraffin, 161 

■ , Air-pump for, 73 

Blowpipe, Paraffin, Reservoir for, 

323 
Boards, Figured, cut from Pitch- 
pine Logs, 15 
Boiler, Boot, 174 

■ , Egg-ended, 173 

for Greenhouse. 173 

,Saddle-shaped,Patitemfor,56 

Bone Apple-scoop, 47 
Book-rack, 229 
Book-rests, 114, 172 
Boot Finisher's Irons, 53 
, French Cork, 17 

Rack, 313 

Shop, Double Seats for, 144 

Boot Boiler, 174 

Bow, Violin, Head and Mount- 
ings of,, 214 

Box for Oil Colours, 190 

Stunip'Moulding, 54 

, Window, for Flowers, 311 

' with Oval Top, 266 

Box-sextant, 93 ' 
Bracket, 278 

, Moulding on Edge of, 78 

Brake Blocks, Waggon, 303 
Brass Cells for Optical Work, 48 

Collar for Dog, 22 

Gas-cocks, 51 

Money Box, 42 

Table-lamp, 212 

Tubes, Bending, 316 

, Machine for Bending, 

286, 316 

Brazing Band-saws, 272 

Key Stems, 311 

Breeding Cage for Small Birds, 
223 

Brick Arch, 278 

, Centering for, 155 

Kiln, 175 

Brickmaker's Clay Waggon, 354 

Brickwork, Model, 'Clock-stand 
in, 149 

Bristle on Waxed Thread, 104 

Bromide Solution, Apparatus for 
Applying to Paper, 166 

Brougham Under-carriage Com- 
passed Bed, 79 

Brush Rack, 206 

Builder's Level, 27 

Trestle, 314 

Building, Sham Timber, 142 

Burner, Incandescent, for Oil, 151 

Buriii-^her tor Silver Mounts, 29 

'Bus Under-carriage, 231 

Butterfly Cases, 306, 

Cabinet, Bamhoo, 132 

, Beadwork, 49 

, Scent, 199 

Cabinet-maker's Steel Scraper, 
Method of Sharpening, 184 



Cabinet-making, Panelled Doors 

in, 284 
Cage, Bird, 223 

for Starlinj or Thru.sh, 169 

Ccimera, Bag Changiug Box for, 

283 

Bellows, Conical, 276 

with Changing Bag, Sheath 

for, 343 
— - Double Repeating Back, 23 

, Enlarging, 275 

, Fixed Focus, Method of 

Enlarging wjth, 121 

, Folding Hand, 220 

, Hand, 822 

, ■, Bamboo Stand for, 336 

--^—, , View-ftnder for, 148 

, Kodak, Enlarging with, 68 

Lens, Hood or Sky Shade 

for, 345 

— ^ . and Stop, 173 

, Majjazine Back for, 283 

, Pinhole, 211 

Plate-changer, 175 

— -, i-plate. Shutter for, 169 

Shutter for taking Photo- 
graphic Doubles, 212 

, Everset. 93 

, Silent, IS . 

, Time and Instan- 
taneous, 187 

, IJnicum, 79 

Stand, Bamboo, 336 

, Stereoscopic, 22 

, Studio, 267 

Swing Back, ^38 

Canoe Mast, JPosition of, 141 
Cap, Circular-moulded Stone, 236 
Carbonic Acid Generator, 329 
Carpenter's Bevel Set-square, 160 

Tool Cupboard, 317 

Try-square, Testing, 50 

Carriage. Invalid, Hood for, 290 

Wheels, Putting Felloes on, 

31 
Cart, Hand, 333 

Panels, Router Planes for 

Boxing out, 243 ' , 

: ; Pony, 96 

Wheels, Measuring Wheel 

I for, 347 

, Putting Felloes on, 31 

Carved Photograph Frame, 60 
Carving Wood, Knife for, 325 
Case for Croquet Mallet, 20 

■ Ferns, 101 

, Insect, 306 

, Jewel, 86 

, -^ — . and Gloves, 140 

, Marble Clock, 284 

for Tea and Sugar, 240 

, Traveller's Sample, 63 

, Turned Wood, for Drum 

Clock, 62 
Case-hardening, Oven for, ,107 
Cask, Oval, Bevels for Joints of, 66 
Cells for Optical Work, 48 
Cement Frame, Oval-shaped, 221 
Centre for Brick Arch, 155 

■ ■ Circle on-Circle Arch, 

171 
Centrifugal Pump, 28 ' 
Chair, Bamboo Ropking, 237 

, Barber's, 98 

, Child's, 116 

, Divan, 214 

, Invalid's Self-propelling,346 

, Marlborough Easy, 122 

, Rush- or Cord-bottomed, 174 

, Spring Seat of, 380 

Changing Bag Camera, 343 
Chapel Pulpit, Small, 131 
Chat-coal, Method of Making, 109 
Chemical Tank for Magic Lan- 
tern, 61 
Chest, Medicine, 139 
— , Tool, for Coach Body 

Maker, 65 
, for Electrical En- 
gineer, 35 



Chest, Tool-, Tenon Saw fastened 

^ to Lid of, 137 
Chicken Rearer, Heating, 14S 
Child's Bedstead, 70 

Chair, 116 

— — Wheelbarrow, 216 

Chimney Breast, Method of Un- 
derpinning, 260' 

Design, 194 

CLrcle-on-Circle Arch, Centre for, 
171 

Circular Mouldings, 78 

, Router for Working, 78 

Saw Attachment for Cutting 

Floor Blocks, 330 

Bench, 286 

Guard, 62 

Cistern, Flushing, 277 

Clay, Side-tipping Waggon f6r,351 

Clip for Scribing Block, 156 

Clock Case, Marble, 284 

in Turned Wood, 62 

, Electric Alarm for. 141 

, Grandfather, Striking Work 

of, 201 

, Lantern, Eight-day Move- 
ment for, 154 

Stand, Model Brickwork, 149 

Striking Movement, 123 

Clockwork Metronome, 9.'v 

Motor for Gramophone or 

Phonograph, 58 

Clothes Rack, 331, 337 

Coach M^er's Tool-chest, 65 

Coal-weighing Machine, Scoop 
forj 342 ' 

Cob, Trotting Sulky for, 318 

Collar, Brass, for Dog, 22 

Colour Box, 190 ' 

Column, Spiral Flute on, 323 

Colujnns for Roof, 226 

Compalssed Bed of Brougham 
"Under-carriage, 79 

Compasses, Beam, 321 

, Trammel, 321 

Compo., Gauge Boxes for, 167 

Concrete Sills and Heads, 111 

Cone, Wrought-iron, 37 

Conical' Bellows for Camera, 276 

Rim, Pattern for, 45 

Copper Foot-warmer, 63 

Pipes, Wiped Joints on, 62 

Copper, Flash-flue Washing, 283 ' 

Cord-bottomed Chair, 174 

Cork Boot, French, 17 

Cornice Moiilding, MjtrC of, 122, 
136 ■ 

Cotes, Pigeons', 219, 296 

Cotton Fibres, 106 

Counter, Simple, 312 

Coupling Shackles, 67 

Crabs, Pot for, 184 

Cradle, Baby's, Stand for, 41 

Cramping Pictui'e Frames, 302 

Crank-shaft of Engine, 102 

Crate for Carrying Pig, 97 

Croquet-mallet Leather Case, 20 . i 

Crucible Steel Furnace, '39 

Cupboard, Glass-fronted Hang- 
ing, 222 

for Carpenter's Tools, 317 

Curtain for Door, 110 

Rails for Bedstead, 104 

Rod, 126, 145 

Curved Wing Wall, 254 > 

Curves, Involute, 226 

, Spiral, Projection of, 110 

Cycle, Block for Supporting, 337 i 

Parts, Qven for Case-hard- 
ening, lO'T 

Shed, 170 ' 

Cylinder-tank System Hot-watei 
Supply, 158, 258 

Damper for Postage Stamps, 276 

Dancing Steps, 177 

Dark Room, Photographer's, 213 

, , Lamp for, 189, 238 

, , Ventilating Sys 

tem for, 181 



Cyclopaedia of Mechanics. 



Decker Oven, 37 
Desk, Roll-top, Shutter for, 291 
Developer, Pyro, Mixing, 203 
Dinins-voom Ingle Nook, 332 
Dipper for Ferrotype Pboto- 

Sraphy, 307 
Distilling 'Water, Apparatus for, 

lOS 

"Wliislvy, Apparatus for, 204 

Divan Cliair, '214 

Settee, 336 

Dog Collar of Brass, 22 

Kennels, 65^,255, 352 

Doll's Wooden Bedstead, 70 
Dolly, Metalworkers' Mandrel, 

113 
Dome, EooC cutting into Side of, 

25 
Diior Curtain, 110 

, Electric Alarm for, 181 

Frame, Elliptical Headed, 13 

Openings; Recording, .243 

, Panelled, in Cabinet- making, 

285 

, , in Joinery, 285 

, Railway Carriage, Sliding 

Sashes in, 349 

, Watertiglit Sliding, 77 

Doorway Porch, 33 

Dovetailing, 24 

Drain~ of House connected to 

Sewer, 23 ^ 
Draughtsman's Pen, Settijig, 47 
Dra^vers, Secret, in Jewel Case, 

SS 
Drawhooks, Locomotive, 297 

, Railway Waggon, 297 

Drawing-pen, Setting, 47 
Drawings, Architects' Perspec- 
tive, 138 
Drilling Watch BtafT, 42 
Drilling-machine, 178 
Dunlop Tyre Valves, Trammel 

Heads made from, 218 
Dutch Barn, Design for, 182 

Easy Chair, Marlbordugh, 122 
Egg supported in Net, 254 
Eight-day Movement for Lantern 

Clock, 164 
Electric Alarm for Clock, 141 

, Shop Door, ISl 

Are Lamp, Hand Feed, 344 

Push, Double-contact, 99 

Electrical Engineer'3 Tool-chest, 

35 
Ellipse, 66 
Elliptic Arch, 201, 209, 211 

Gothic Arch, 196 

Elliptical Headed Door Frame, 13 
Embroidery Frame, 133 
Engine Crank-shaft, 102 

Indicator Diagi-ams, 92 

for Pile Driving, 166, 316 

■ Rods, 84 

Engineer, Electrical, Tool-chest 

for, 86 
Enlargements, Photographic, 121, 

127 
Enlarging Camera, 275 

— , Kodak as, 68 

Lantern, 31, 277 

Entrance Gate Tenons, 124 
Envelopes for Insects, 306 
Bverset Photographic Shutter, 93 
Extension Ladder, 241 

Fan, Blowing, for Forge, 319 
Felloes, Method of Putting, on 

Wheels, 31 
Felt and Corrugated Iron Roof, 

225 
Fender Stool, 264 
Fern Case, 101 
Ferrotype Photography, Bath 

and Dipper for, 307 
Fibres of Linen, Cotton, Wool, 

and Silk, 106 
Filter, Automatic Sewage, 203 

Beds, 215 

for Oil, 100 

Filtration of Oils by Heat, 

Apparatus for, 125 
Fir, Scotch, 816 

, Spru(;e, 315 

Fireguard, 71 

Firelighters, 268 

Fishing, Folding Gnlffor, 179 



Fishing, Landing Net for, 157 

Line Knots, 234 

Reel, 237 

Stool, Three-legged, 21 

Flags, Signal Code, 351 
Flash-flue Washing Copper, 283 
Flashings, Lead, for Roofs, 331 
Flitched Beam, Section of, 162 
Floor, Assembly-room, Joists for, 

217 

Blocks, Cutting, 330 

■ Boards, Tightening, 119 

supported by Girder, 190 

, Wood-block, 246 

Flower Pot Board, Window, 326 

Stand, 246 

■ Window Box, 811 

Flues of Washing Copper, 283 

Flushing Cistern, 277 

Flute, 152 

Flute, Spiral, on Column, 323 

Folding Gaff" for Salmon Fishing, 

170 

Hand Camera, 220 

Leaf of Kitchen Table, 179 

Stand for Baby's Cradle, 41 

Stool, Angler's, 21 

Table, 143 

Food Bin for Poultry, 130 
Footstool, Round, 2S1 
Foot-warmer, Copper, 62 
Forge, Blowing Fan for, 319 
Fountain for Greenhouse, 340 
Fowls' House, 339 
Frame, Apparatus for Bevelling, 

270 

-t Carved Photograph, 60 

■ covered with Pluah, 108 

, Cramping, 302 

, Door, Elliptical Headed, 13 

, Embroidery, 133 

, Oval, in Cement, 221 

, Oxford, 247 

for Wire Blind, 64 

French Cork Boot, 17 

Whip Top, 286 

Furnace, Crucible Steel, 39 
for Waggon Springs, 59 

Gaff for Salmon Fishing, 179 
Galvanometer, Watch-case, 66 
Garden Pump, 331 

Tripod for Telescope, 94 

Vase, 228 

Wicket Gate, 320 

Gas Generator, Acetylene, 67, 282 

, Carbonic, 329 

Stove Clothes Rack, 337 

■ for Heating Laundry 

Irons, 242 
Gas-cocks, Brass, 51 
Gate, Entrance, Tenons for, 124 

, Garden Wicket, 320 

Gauge Boxes for Co(npo., 167 

for Inlaying Purfliug on 

Violin, 308 

; Stringing, 164 

• — - marking Positions of 

Studs in Upholsteiy, 210 ■ 

, Pencil Marking, 133 

Gauged Arch, 235 
Gedge's Draw-hook, 297 
Girder for Roof, 226 

Sections, 161 

to support Floor, 190 

Glass Louvre Ventilators, 34 
Roof, Preventing Moisture 

Dropping from, 299 

Silverer's Table, 72 

, Wheels for Bevelling and 

Polishing, 314 
Glass-faced Swinging Sign, 295 
Glass-fronted Cupboard, 222 
Glazing Window Frames, 109 
Glazing-knife, 343 
Glove and Handkerchief Case, 140 
Goods Hoist, 31U 

Lift, 320 

Gothic Aroli, Elliptic, 195 
Gradient o! Watercourse, Setting 

out, 334 
Gramophone, Clockwork Motor 

for, 68 
Grandfather Clock, Striking Work 

of, 201 
Granite Dressing Tools, 205, 238; 

282 
Greenhouse Boiler, 173 



Greenhouse Fountain, 340 

, Top Rail of, lis 

Greenstuff Food, Rack for, 334 
Grocer's Hoist, 819 
Grooving Sashes, Machine for, 259 
Guard for Circular Saw, 62 

Fireplace, 71 

Guns, Air, 256 
Gutters, Cast-iron, 202 

Hair Mattress, 207 

Halation in Negatives, Diagram 
showing, 313 

Hall Racks, 331, 346 

Hammer, Scubbling, 61 

Hand Camera (see Camera) 

-■ — Cart, 333 

— — Feed Arc Lamp, 334 

Guards for Singlf-sticks, 

308 

— Shears for Sheet Iron', 210 

Handkerchief Case, 140 

Hanging' Clipboard, 222 

Hat Riiolis, 331, 346 

Heaped Material, Method of De- 
termining Contents of, 210 

Hearth, Tile, 244 

Heating Chicken Rearer, 148 

by Hot-water, 236, 253 

Laundry Irons, Stove for,- 242 

, Steam, System of, 228 

Hinge of Screen Frame. 94 

Hip Rafter, Bevel of, 57 

Hoist, Grocer's, 319 

Hood for Camera Lens, 345 

— — Invalid Carriage, 290 

Hook, Reed, for American Or- 
gans, 299 

for Twisting Straw Bands, 

309 

Horse for Mortising Wheel Naves, 
135 

Horses, Stocks for Shoeing, 43 

Hot Box for Negatives and Lan- 
tern Slides. 26 

Hot-air Oven, i32 

Hot-water Apparatus, 127, 158, 
175 

Pipes, Joint for, 347 

Systems of Heating, 235, 258 

Towel Airer, 179 

House Drain Connection to Deep 
Sewer, 23 

House, Fowls', 339 

, Pigeons', 219, 296 

■ Porch, 33 

Hydraulic Gradient, 263 

Mean Depth, 68 

Bam, 163 

Incandescent Burner for Oil, 151 
Indicator Diagrams of Engine, 92 
Ingle Nook, 342 

Inlaying Puifling on Violin, 
Gauge for, 308 

' Stringing. Gauge for, 164 

Insect Cases, 306 
Invalid's Bed-rest, 139 

Carriage, Hood for, 290 

Self-propelling Chair, 345 

Involute Curves, -226 

Iron, Corrugated, Roof of, 226 

Roof, ISO 

, Sheet, Hand Shears for, 210 

Irons, Shoe Finishers', 53 

Jack Plane with Side Slip, 117 

Rafters, 209 

Jewel Box and Scent Cabinet 
combined, 199 

Case with Secret Drawers, 86 

, Glove, and Handkerchief 

Case, 140 

Joinerv, Panelled Doors in, 285 

Joint for Hot-water Pipes, 347 

. Oblique, Mortise-and-tenon, 

190 

, Pavodilos, 98 

, Plumber's Underhand, SS ' 

, Wiped, on Copper Pipe, 62 

Joints ot Oval Cask, 66 

Joi-sts for Floor ot Assembly- 
room, 217 

Kennels, Dog, 55, 265, 352 
Kerbing, Curved, 217 
Key Steins, Brazing, 311 
, Stopcock, 271 



Kiln for Bricks, 175 

King-post Truss, Hipped End of, 
328 

Kitchen Table, 171 

Folding Leaf and Sup- 
ports, 179 

Knife, Glazing, 343 

, Stopping, 343 

, Umbrella-maker's, 164 

, Wpo'l-carving, 325 

Knots fbr Fishing Lines, 234 

Kodak as Enlarging Camera, 68 

Ladder, Extension, 241 

, Step, Setting out Side of, 30 

Lamp for Dark-room, 189, 233 

Hand Feed Arc, 344 

, Street, Door Catch of, 92 

, Table, 212 

Landau Head, 188 
Landing Net, Fisherman's, 157 
Lantern Clock, Eight-day Move- 
inent for, 154 

for Enlarging, 31, 277 

— ~ Light, Semi-octagonal, Bevel 
for Hips to, 193 

, Magic, 31 > 

- — • , Acetylene Gas Gen- 
erator for, 67 
, , Chemical Tank for, 61 

Slides, Apparatus for 

Making. 95 

, Hot Box for, 26 

Lath, Detachable, for Table, 66 
Lathe Beading Spindle, '288 

, Overhead ■ Arrangement 

for, 192 

Slide-rest, Tool-holder for, 

191 

, Wood Chuck for, 14 

Latrine on Board Ship, 341 
Laundry Stove for Heating Irons, 

242 
Lavatory Mirror, 186 
Lead Bays for Ogee Roof, 280 
— '— Flashings " Burnt-in " to 

Stone, 229 

Flashings for Roofs, 331 

Leakage of Water, Instrument 

for Locating, 271 
Leather on Band-saw Wheel, 262 
, Belts, Diagram of Power 

Transmission by, 99 

Case for Croquet Mallet, 20 

■■ Purses, 261 

Legs of Bam boo Table, 128 
Lens, Camera, Hood or Sky 

Shade for, 345 
Lenses, Periscopic, 327 

, Photographic, 324 

, Rectilinear, 327 

Letter-bdx, Shaet-metal, 291 
Level, Builder's, 27 
Lift, Goods, 320 
Linen Fibres, 106 
Lines, Fishing, 234 
Lobster Pot, 184 
Locomotive Draw Hook, 297 

Reversing Gear, 'Stephen- 
son's, 213 

Log, Ship's, Working, 169 
Louvre Ventilators, Glass, 34 
Louvred Thermometer Screen, 71 
Lumber, Apparatus for Arti- 
ficially Seasoning, 107 

Magazine Back for Camera, 283 
Magic Lantern, 31 
— , Acetylene Gas Gener- 
ator for, 67 
, Chemical Tank for, 01 

— - Slides, Apparatus for 

Making, 95 

Mailcart, 1S3 

Mandrel Dolly, Metalworkers', 

lis 
Mangle Shafts, Press for, 40 
Map, Ordnance, 58 
Marble Clock Case, 284 
Marjting Gauge, 133 
Marlborough Easy Chair, 122 
Mast in Canoe, Position of, 141 
Mattress, Hair, 207 
Measuring Wheel for Cart Wlieels, 

347 
Medieine Chest, 139 
Metal Plates, Levelling. 208 
Metalworkers' Mandrel Dolly, 113 



Cyclopsedia of Mechanics. 



-Metronome, Clockwoi-lc, 95 

, Simple, 19 

Microscope Cell 'Woilv, 43 
Middjan Stead, Covered, 269 
Mill, Saw, 257 

Mirror for Bath or Lavatory, 1 86 
Mitre Box, 136 

Lines, Setting out, 239 

of Raking Cornice, 122 

'Mitring Cornice Moulding, 136 
Model Brickwork Cloek-staud, 

149 

Pumping 'Windmill, 310 

— - Yacht Sail Plans, 168, 184 
Money Box, Brass, 42 
Mortise-and-lenon Joints, 

Oblique. 196 
Mortising Wheel Naves, Horse 

for, 135 
Mortuary Bier Stand, 73 
Moths, Cases for, 306 
Motor, Clockwork, for Gramo- 
phone and Phonograph , 58 
,' Reciprocating Water, 258, 

34'2 

, Water, '39 

Moulded Stone Cap, 236 
Moulding-cutters, Machine for 

Grinding, 216 
Mouldings on Arches^ 146 

, Circular, Working, 73 

, , Router for Working, 78 

, Intersection of, 197 

, Mitred Cornice, 122, 136 

for Railj^ay Carriages, 191 

, Mitre Lines for, 239 

— ~, Scratch Plane for, 163 
, Burnisher 

for, 29 
Mounting Stereoscopic Prints, 63 
Mounts, Silver, Burnisher for, 29 

for Stag's Antlers, 77 

Tobacco Pipes, 29 

Music Shelf for Piaao, 338 

Negatives, Diagrams Illustrating 

Halation in, 313 

, Hot Box for, 26 

^— , Toorfor Retouching, 262 
Net, Egg supported in, 254 

, Landing, 157 

Newspaper-rack of Bamboo, 123, 

134 
Nook, Ingle,- 382 

jpak, Wainscot, 224 

Octagonal Fountain for Green- 

- house, 340 
Ogee Roof, Lead Bays for, 280 
I Oil Burner, Incandescent, 151 
- — '■ Filter, 100 
- — ■ Filtration by Heatj 125 
Oil-colours, Box for, 190 
Omnibus XJnder-carriage, 231 
Opal Printing Frame, 236 
Opera Glass Lens, Photography 

with, 336 
Optical Square, 114 

Work, Brass Cells lor, 43 

OMnancc Datum, 58 

Map, 58 

Oval, 66 

Baskets, Repairing, 309 

Cask Joints, Bevels for. So 

Frame in Cement, 221 

Top Wooden Box, 266 

Oven, Bakdr's Steam-heated, 37 

foi' Case-hardening, 107 

, Hot-air, 132 

Oxford Picture Frame, 247 

Panel Plane with Side Slip, 117 
Panelling with Veneers, 126 
Panels, Cart, Router Planes for 

Boxing out. 243 
Paper, Apparatus for Applying 
Bromide Solution to, 166 

, Photographic, Method of 

Preparing, 233 
ParafRii Blow-lamp', 151 

, Air Pump for, 73 

■ Blowpipe Reservoir, 323 

I Parisian Phaeton, 197 
Pasteboard Tube Umbrella- 
stand, 252 
Pattern for Compassed Bed nf 
1 Brougham Under-carriage, 79 
I . Conical Rim, 45 



Pattern for Fountain, 340 

Saddle Boiler, 56 

Tuyferc Bend, 284 

- — ■ Wronght-iron Cone, 87 

Pavodilos' Joint in Flooring, 93 
Pedestal for Table, 120 
Pen, Ruling, Setting, 47 
Pencil Marking Gaugd, 133 
Pehscopio Lenses, 327 
Perpetual Calendar Watch, 44 
Perspoctive Drawings, Archi- 

tect's, 138 
Phaeton, Parisian, 197 - 
Phonograph, Clockwork Motor 

for, 58 
Photograph Frame, Carved, 60 
Photographer's Dark Room, 213 

_£ Lamp, 189, 233 

■ ■ , Ventilating Sys- 
tem lor, 181 

■ Hand Feed Arc Lamp, 344 

Photogr.ipliic Camera (see 
Camera) 

■ Developer, Apparatus for 

Mixing, 263 

Doubles, Camera Shutter 

for Taking, 212 

Enlargements, 121, 127 

Enlarging Camera, 275 

Lantern, 31, 277 

. ^ Kodak as, 68 

Lenses, 324 

■ Negative, Halation in, 313 

— '- Negatives-, Hot Box for, 26 
, Tool for Retouching, 

262 

Paper, Preparing, 166, 233 

Plate-changing Anungement 

in Hand Camera, 175 

Print Washer, 126 

Printing Frame, ^-plate, 203 

for Opals, 236 

Prints, Apparatus for Test- 
ing, 275 ' 

, Vignetting, 14 

Shutters, IS, 79, 93, 169, 187, 

212 
Stereoscopic Prints, Method 

of Mounting, 53 

Studio, 274 

Camera, 267 

^ , Temporary, 345 

Photographing Cyclists, Block 

used in, 337 
Photographs, Postage Stamp, 305 
P)iotography, Stereoscopic, 

Camei-a for, 22 

with Telescope, 336 

, Wet-plate, Wire Rests used 

in, 100 
Piano Music Shelf, 338 
Picture Frame, Cramping, 302 

, Oxford, 247 

Pictures, Triad, 75 

Pig, Crate for cari-ying, 97 

Pigeon Cote, 219, 296 

Pile Driving, Engine for, 165, 316 

Piles, Drivi^ig, on Batter, 346 

Piles, Thermo-electtie, 90 

Pillar, Turned, Cutting Slot in 

Top of, 65 
Pinhole Camera, 211 
Pipe, Copper, Joint in, 62 

, Hot-water, ^Joint for, 347 

, Hydraulic, Mean Depth of 

Liquid in, 68 

, Lead, Joint in, 88 

Pipe-mount, Silver, 29 

, , Burnisher for, 29 

Pipes, Tobacco, Rack for, 163 
Pitch-pine Logs, Figured Boards 

cut from, 15 
Plane, Jack, with Side Slip, 117 

, Router, 243 

, Scratch, for Mouldings, 168 

Plate Stand, 344 
Plate-changing Arrangement in 

Hauil Camera, 175 
Plate-glass Silveror's Table, 72 
Plates, Thin Metal, Method of 

Levelling, 203 
Plough, Sqow, 72 
Plugs, Watch Cylinder, Puncli 

fbr removing, 152 
Plumber's Underhand Joint, 88 
Plumbing Work on Board Troop- 
ship, 341 
Plush-covered Frames, lOS 



Pointed Brickwork, 115 
Polishing Glass, Wheels for, 314 
Pony Cart, 96 

Trap, 16 

Porch, 33 

Portiere Rod, 125, 145 

Portraiture, Camera Swing Back 

in, 338 
Postage Stamp Damper, 276 

, Photographs, 305 

Pots, Flower, Window Board for, 

326 
Poultry Food Bin, 130 

, Rack for, 334 

Power Transmission by Leather 

Belts, Diagram of, 99 
Prawn Trap, 186 
Press for Mangle Sliafts, 40 

Ttcmsers, 154 

Prints and Printing Frames, 

Photographic (seo Photo- 
graphic) 
Pulpit for Small Chapel, 131 
Pulsometer, 74 
Pump, Air, for !Blow-larap, 73 

, Centrifugal, 28 

, Garden, 331 

Pumping Windmill Model, 310 
Punch for reriioving Cylinder 

Plugs. 152 
Purfling Gauge, 308 
Purses, Leather, 261 
Push, Double-contact Electric, 99 
Putty Knives, 343 
Puttying Window Pane, 109 
Pyro Developer, Apparatus for 

Making, 263 

Rack, Bamboo, for Newspapers, 

123, 134 

for Books, 229 

Boots, 313 

^ Brushes, 206 

Clothes, 331 

Greenstuff Food, 334 

Hall, 331, 346 

for Hats, 331, 346 

Poultry Pood. 334 

Rifles and Belts, 260 

Sticks, 346 

• Tobacco Pipes, 163 

Tumbler, 111 

, Umbrella, 346 

, Wall, for Clothes, 337 

Rafters, Bevels for, 57, 165 

, Jack, 209 

, Valley, 209 

Railway Carriage Doors, Sliding 

Sashes in. 349 

Moulilings. 191 

Coupling Shackles, 67 

Waggon Bi-ake Blocks, 303 

Draw Hook, 297 

Springs, Furnace for, 59 

Ram, Hydraulic, 163 
Reciprocating Water Motor, 298 

' , Regulator foi:, 342 

Rectilinear Lenses, 327 
Reed-hook lor American Organs, 

299 
Reel for Fishing Rod, 237 
Reflected linage, Obtaining, 162 
Reservoir for Paraffin Blowpipe, 

323 
Retaining Wall, Diagram of 

Pressure of, 166 

for Sunk Roadway, 204 

Retouching Negatives, Tool for, 

262 
Reversing Gear^ Stephenson's, 

213 ~ 

Ridge Roll of Roof, 117 
Rifle and Belt Racks for Tent 

Pole, 260 
Riffler, 325 

Rim, Conical, Pattern for, 45 
River, Method of Taking Cross 

Sections of, 265 
Roadway, Sunk, Retaining Wall 

for, 204 
Rocking Chair, Bamboo, 237 
Roll-top Desk, Shutter for, 291 
Roof, Corrugated Iron and Felt, 

225 

, Covering, with Zinc, 129 

cutting into Side of Dome, 25 

, Girders and Columns for 

carrying, 226 



Roof, Glass, Preventing Moisture 

Dropping from, 299 

Hip Rafter, Bevel of, 57 

, Iron, 180 

, Lead.Flashings for, 331 

, Ogee, Lead Bays for, 280 

, Ridge Roll of, 117 

Slate, Replacing, 281 

Truss, Hipped End of, 328 

Ropes, Straw, Twisting Hook for, 

309 
Router Planes, 243 
Ruling Pen, Setting, 47 
Rush-bottomed Chair, 174 

Saddle-shaped Boiler,' Pattern 
for, 56 

Sail Plans, Model Yacht, 168, 184 

Salinometer, 119 

Salmon Fishing, Gaff for, 179 

Sample Case, Traveller's, 63 

Sash Bars and Rails, 198 

Sashes, Double, for Deadening 
Noise, 287 

, Machine for Grooving, 259 

, Sliding, in Railway Carriage 

Doors, 349 

Saucepan Covers, 112 

Saucer Ornamentation, 38 

Savings Bank or Money Box, 42 

Saw, Band (see Band-saw) 

, Circular, arranged for Cut- 
ting Floor Blocks, 330 

, , Bench for, 285 

, , Guard for, 52 

Mill, 257 

, Tenon, fastened to Tool- 
chest Lid, 137 

Vice, 60 

Saw-sharpening Machiiip, 247 

Scabbling Picks and Hammers, 
61, 20.1, 232 

Scent Cabinet and Jewel Box 
Combined, 199 

Scoop for Apples, 47 

for Coal-weighing Machine, 

342 

Scotch Fir, ai5 

Scraper, Cabinet-maker's, Method 
of Sharpening, 134 

Scratch Plane for Woi king Mould- 
ings, 168 

Screen Frame Hinge; 94 

, Stephenson's Thermometer. 

71 

- — -, Vestibule, l&l 

Scribing Block, 144 

, Clip for, 156 

Seat, Spring, of Armchair, 330 

Seats for Shop, 144 

Secret Drawers, Jewel Case with. 
86 

Segmental Openings, Splayed 
Linings to, 350 

Set-square, Bevel, 160 

Settee, Divan, 335 

Sewage Filter, Automatic, 203 

Irrig.ition, 263' 

Sewer, House Drain Connection 
to, 23 

Sextant, Box, 93 

Shackles, Railway Coypling, 67 

Sham Timber Building, 142 

Sharpening Saws, Machipe for, 
247 

Shears, Hand, for Sheet Iron, 210 

Sheath, Hand Ct^mera, 343 

Shed for Storing Cycles, 170 

Sheet-metal Fountain for Green- 
house, 340 

Letter box, 291 

, Waggon, Side-tipping, 354 

Shelf Bracket, Working Mould- 
ing on Edge of, 78 

for Piano, 338 

Shields for Mounting Antlers, 77 

Ship's Latrine, 341 

Log, Working, 159 

Slop Shoot, 341 

Ventilator JPatterns, 1j7 

Washhouse, 341 

Watertight Sliding Door, 77 

Shoe Finisher's Irons, 53 

Sliooting Gallery Target, 97 

Shop Counter, 312 

Door Electric Alarm, 181 

, Double Seats for, 144 

Front, Section of, 34 



10 



Cyclopaedia of Mechanics. 



Shutter, Camera, on Unicum 

Priiiciiile, 79 

, Everset Photographic, 93 

for J-plate Cameia, 109 

for Roll-top Desk, 291 

, Silent, for Camera, IS 

for talting Photograpliio 

Doubles, 212 
Side-tipping Waggon for Clav, 

854 
Sign, Glass-faced Swinging, 295 
Signal Code Flags, 351 i 

Signboards, Triad, 75 
Silk Fibres, 106 

Tassels, Apparatus for Mak- 
ing, 274 
Sills, Concrete, of Window, 111 
Silver Pipe-mount, 29 

■ , Burnisher for, 29 

Silvering GFass, Table used in, 72 
Singlestick Handguards, 308 
Sky Shade for Camera Lens, 345 
Slate Roof, Replacing, 281 
Sledge, 54 \ 

Slide-rest, Tool-holder for, 191 
Slides, Lantern, 95 

, ; Hot Box for, 26 

Slidipg Door, Watertight, 77 
Sashes in Railway Carriage 

Doors, 349 
Slop Shoot on Board Ship, 341 
Slot. Cntting, in Top of Turned 

Pillar, 65 
Smoker's Companion, 163 
Snow Plough, 72 
Soap Box and Tumbler Rack, 111 
Solfit of Splayed Linings, 350 
Sounding Tube for ^ Locating 

Water Leakage, 271 
Span Roof Fowl-house, 839 
Specimen Woods, Set of, 271 
Spill Cutter, 156 
Spiral Curves, Projection of, 110 

Flute on Column, 323 

Spirit-level Tubes, 207 

Splayed Linings tn Segmental 

Opening.s, 350 
Spokes of Wheels, Apparatus for 

Holding, 103 
Spring Seat of Armchair, 330 
Springs. Waggon, Furnace for, 59 
Spruce Fir, 315 

Square Baskets, Repairing, 30!) 
Square, Carpenter's, Testing, 50 
- — , Optical, 114 
Stag's Antlers, Mounting, 77 

-, Mounts for, 77 

Staircase Well Development, 187 
Stamp Photographs, 305 
Stamps, Postage, Damper for, 276 
Stand tor Baby's Cradle, 41 

, Bamboo, for Camera, 336 

, Bier, for Mortuary, 73 

for Flowers, 246 

in Model Brickwork for 

Clock, 149 

for Telescope, 94 

, Toast, 344 , 

, Tripod, for Plate, 344 

Starling's Cage, 169 
Steam Heating, System of, 228 
Steam-heated IBaker's Oven, 87 
Steel, Crucible Furnace for, 39 

Scraper, Cabinet-maker's, 

Method of Sharpening, 134 

Stencil Plate, 82 
Step Ladder, Side of, 30 
Stephenson's Reversing Gear, 218 
Stephenson's Louvred Ther- 
mometer Screen, 71 
Steps, Balanced or Dancing, 177 

, Stone, Repairing, 218 

Stereoscope, 51 
Stereoscopic Camera, 22 

Prints, Mounting, 63 

Stick Hack, 346 
Still for Water, 108 

Whisky, 204 

Stock Hoops for Wheels, 262 
Stocks for Shoeing Kicking 

Horses, 43 
Stone Cap, Circular-moulded, 236 
— ^, Lead Flashings " Burnt-in " 
to, 229 



Stone SLups, Repairing, 218 
Stool, Foot, 281 

, Three-legged, for Angler, 21 

— , Upholstered Fender, 264 
Stopcocks Key and Sounding 

Tube Combined, 271 
Stopping Knife, 848 
Stove for Laundry Irons, 242 

Rack for Drying Clothes, 3R7 

Straw Band Twisting Hoolt, 309 
Street Lamp Door Catch, 92 
Stretchers lor Trousers, 84 
Striking Movement of Vienna 

Regulator, l23 
Stringing, Gau^e for Inlaying, 164 
Studio Camera, 267 

, Photographic, 274 

, Temporary Photographic, 

345 
Stump Moulding, Box for, 94 
8ugar and Tea Case, 240 
.Sulky, Trotting, 318 
Survey, Method of Plotting, 185 
Surveyor's Box Sextant, 93 
Swing, Baby's, 205 

Curtain Rails for Bed- 
stead, 104 

Swinging Sign, 295 

Table. Bamboo, Legs of, 128 

, Bedroom, 36 

, BiUiird, Corner of, 153 

, Folding, 148 

Fi-amework, 223 

, Glass Silverer's, 72 

, Kitchen, 171 

' , , Folding Leaf and 

rrupports of, 179 

Lamp, Sheet Brass, 212 

Pedestal, 120 

Stand for Plates, etc., 844 

Top, Detachable LaUi for, 56 

Trestles, 289 

-, Writing, 105 

Tank, Chemical, for Magic Lan- 
tern, 61 

Pleasuring Liquid from, 203 

, Systeraof Boiling Water in, 

200 

Target for Shooting Gallery, 97 

Tassels, Silk, Apparatus for Mak- 
ing, 274 

Tea and Sugar Case, 240 

Tea-table Trestles, 289 

Telescope Cell Work, 48 

, Photography with, 336 

TriiJOd Starxl, 94 

Telescopic Beam Compass, 321 

Tenon Saw fastened to Tool-chest 
Lid, 137 

Tenons for Entrance Gates, 124 

Tent Pole, Rifle and Belt Racks 
for, 260 

Tester Head for Bedstead, 198 

Testing Brougham Under-car- 
riage, Metliod of, 79 

Carpenter's Try-square, 50 

Thermo-electric Piles, 90 

Thermometer Screen, Stephen- 
son's, 71 

Thread, Waxed, Bristle on, 104 

Thru.sh, Cage for, 169. 

Tile Hearth, Removable, 244 

Timber Buildings, Sham, 142 

, Diagram showing Strength 

of, 208 . 

Tinmen's Workshop, Plan of, 84 

Toast Stand, 344 

Tobacco-pipe .Mount, 29 

, BurnMher for, 29 

Rack, 163 

Tool Cupboard, Caipenter's, 317 

Tool-chest for Electrical Engin- 
eer, 35 

Light Coach Body 

Maker, 65 

Lid, Tenon Saw fastened to, 

1:I7 
Tool-holder for Slide-rest, 191 
Tools for Dressing Granite, 205, 

288, 282 
Retouching Negatives, 

262 
Top, French Whip, 286 



Towel Airor, Hot-water, 179 

Tracery Window, 287 

Trammel Heads, 218 

Trap for Prawns, 186 

Trap for 18-lmnds Pony, 16 

Travellers Sample Case, 63 

Trav, Washing, 206 

Trellis Work, 145 

Trestle, Builder's, 314 

Trestles for Tea-tables. 289 

Ti'iad Pictures, 75 

Signboards, 75 

Tripod Plate Stand, 344 

Stand for Telescope, 94 

Troopship's Latrihe, 341 

Slop Shoot, 341 

Washhouse, 341 

Trotting Sulky, 318 

Trousers P;'ess,.154 

Stretchers, 84 

Truss, King-post, Hjpped End 
or, 328 

Try-square, Method of Testing, 50 

Tubes, Brass, Bending, 316 

, , Machine for Bending,' 

286, 816 

, Pasteboard, Umbrella- 
stand made from, 252 

— , Spirit-level, 207 

Tuck Pointing of Brickwork, 115 

Tumbler Rack and Si tap Box, 111 

Turned Pillar, Cutting Slot in 
Top of, 65 

Wood Clock-case, 52 

Tuyere Bend Pattern, 284 

Twisting Hook for Straw Bands, 
309 

Umbrella Cover Pattern, 82 

Rack, 340 

Umbrella-maker's Stock Knife, 

164 
Under-carriage of Brougham, 

Compa^^sed Bed of, 79 

, 'Bus, 231 

Underhand Joint, Plumber's, 88 
Underpinning Chimney Breast, 

260 
Unicum Type Camera Shutter, 79 
Upholstered Fender Stool, 264 
Upholstery, Gauge for Marking 

Positions of Studs in, 210 

Valley Rafteis, 209 

Vase foi- Garden, 228 

Veueer Panels, 128 

Ventilating System for Dark 
Room, 181 

Ventilator, Glass Louvre, 34 

, Ship's, Patterns for, 157 

■ in Shop Front, 34 

Vestibule Screen, Removing, 101 

Vice for Saws, 60 

Vienna Regulator Striking Move- 
ments, 123 

View-finder for Camera, 148 

Vignetting Photogi-apiis, 14 

Vinegar Making A])paratus, 265 

Violin Bow, Head and Mount- 
ings of, 214 

Purfling Gauge, 308 

Waggon Brake Blocks, 308 

, Side-tipjiing, 354 

— - Springs, Furnace for, 59 
Wheels, Method of Setting 

out, 178 (see also Wheels) 
Waggonette Head, 279 
Wainscot Oak, '^24 
Walking-stick Rack, 346 
Wall and Curbing, (Jurved, 217 

, Curved Wing, '264 

Racks (see Rack) 

, Retaining, Diagram of 

Pressure on, 166 
, , for Sunk Roadway, 

204 
Washer for Photographic Prints, 

126 
Washhouse on Board Ship, 841 
Washing Copper, Pksh-nue, 283 

Tray, 206 

Watch Cylinder Plugs, Punch for 

Removing, 152 



Watch Depth, Testing, 200 

r Lever Escapement, Method 

of Deptliing, 173 

, Perpetual Calendar,Mech^n- 

isiii of, 44 

Staff, Method of Drilling, 42 

Watch-case Galvanometer, 66 

Water, Aerated, Machine for 
Making, 329 

, Apparatus for Boiling. 'iuO 

, Distilling, 10s 

Filter Beds, 21.5 

Leakage, Instrument for 

Locating, 271 

Motor, 39 

, Reciprocating, 298, 342 

— - Supply System, Temporary, 
230 

Watercourse Gradient, Setting 
out, 324' 

Watertight Sliding Door, 77 

Waited Thieart, Bristle on, 104 

Weighing Machine, Coal, Scoop 
for, 342 

Wells Apparatus for Measuring 
Distances, 294 

Wheel, Measuring, for Cart 
Wheels, 347 

Naves, Horse for Mortising, 

135 

— I- Spokes, Apparatus for hold- 
ing, 103 

Wheelbairow, Child's, 216 

i Frame, 32 

, Small, 176 

Wheels, Bevelled Stock Hoops 
for, 262 ^ 

r for Bevelling and Polishing 

Glass, 314 

, Cart, Measuring Wheel for, 

347 

, Machine for withdrawing 

Axle Boxes fj'ora, 126 

, Putting Felloes on, 81 

, Waggon, Setting out, 178 

Wheelwri^lit's Horse for Mortis- 
ing Wheel Naves, 135 

Whip-top, French, 286 

Whiskey, Apparatus for Distil- 
ling, 204 

Wicket Gate, 320 

Windmill, II ode) Pumjiug, 310 

Windiiw Board for Flower Pots, 
826 

Box for Flowers, 311 

Pane, Glazing, 1C9 

Sashes, Double, for Deaden- 
ing Noise, 287 

Sills and Heads, Concrete, 

111 

, Tracery, 287 

Windsoi- Chair fitted as Barber's 
Chair, 98 

Wing Wall, Curved, Projection 
of, 254 

Wiped Joint on Copper Pipe, 62 

■ Lead Pipe, 88 

Wire Blind, Frame for, 64 

■ Rests used in Wet-plate 

Photography, 100 ' 

Wood Bedstead, Child's or 
Doll s, 70 

Block Floor, 245 

Blocks, Apparatus for Cut- 
ting, 330 

Chuck in Sections, 14 

■ Panelling with Veneers, 128 

Seasoning Apparatus,! '107 

Woodcarving Knife, S25 

, Specimens, Set of, 271 

Woodworking Lathe, Beading 
Spindle for, 288 

Wool Fibres, 100 

Workbox for, Beadwork, 49 

Workshop, Tinmen's, Plan of, 84 

Worm Screws on Banjo, 115 

WringiuLT Machine, 2'r 

Writing Table, 106 

Yacht, Model, Sail Plan for, 168, 
184 

Zinc, Roof covered with, 129 
iSinc Stencil Plate, 82 



CASSELLS 

CYCLOPAEDIA OF MECHANICS. 



Refilling Fitzroy Baronreter.— It Is not an easy 
matter for an Inexperienced person to till a barometer 
px'operly. The tube and mercury must first be made 
, warm. The mercury may be heated to the boiling point 
of water In an Iron vessel ; a. vessel having tin in its com- 
position must on no account Ipe used. The glass should be 
warmed sufficiently to ensure the evaporation of all, 
moisture. Make a paper funnel having but a very small 
aperture and pour in the, mercury, whose impurities 
will cling to the paper funnel, and test tor correct 
amount with a standard barometer. Be careful that 
air does not enter with the mercury. If ^.n odd air^bubble 
appears, send up a little more to collect, and send up 
to the top what has already entered. 

, Making Lantern Slides.— Lantern slides are made 
from prints, photographs, etc., in the following way. 
MaKe a negative of the subject by copying in the 
camera in the usual way. Eoeus the picture sharply 
within a square 3iin. by 31 In., leaving iin. each way 
for binding and masking. Copying is merely photo- 
graphing, at close quarters. If the camera will not 

, extend far enough to obtiiln a picture of the required 
size, the lens , and front can be removed from the 
camera proper, and the camera lengthened by attach- 
ing ,to it a box at one end of which the lens and front 
can be fitted, the join between the box and the camera 
being covered with a dark cloth. From the negative 
>thus obtained a lantei'n slide may be made either by 
contact or through the camera. Making slides by 

, contact is the simpler plan if the lantern plate is 
large enough to contain the whole' of the picture. 
Place the lantern plate in contact with the nega- 
tive (film to film) in the dark room and expose, to 

. , the light of a gas ilame -, a thin image is developed. 
Bromide plates are the least troublesome to use, 
and a simple developer is metol and soda. After 
development, the plata is fixed and washed as usual. 
Vhen the negative is dry a mask |s laid on the film 
side, and over the mask is placed a carefully cleaned 
cover glass; the two glasses are then bound together 
with strips of black -gummed paper. The glasses should 
be gripped firmly in the centre with the thumb and fore- 
finger of the left-hand, and the moistened paper laid 
along the top edge in position and smoothed gently 
•towards the two ends, when dry, do the opposite side, 
then the remaining sides. Juastly, clean oft any gum 
and finger marks. For copying throught the camera, 
the negative should be fixed in the bottom of the box, 
glass side out (so that the sides bf the box shade the 
film), and either .placed on, a slanting board pointing to 
the clear sky^ or set up on a table in front of -a lamp 
shaded with a sheet of, ground glass. The picture Is 
then focussed to the desired size, and the exposure is 
made by daylight, if possible, or by artificial light, such 
as a lamp or a Jiiece of magnesium ribbon burnt behind 
ground glass. Masks can be bought; they are used to 
define the extent of the picture to be shown on the 
screen.. The cover glass protects the film of the negative. 
The binding strips can also be bought;, their lise is 
obvious. A white spot (a smaU circular piece of white 
paper) is placed in each of the top corners of the nega- 
tive as a guide to the lantern operator. When photo- 
graphs or book prints are to be copied on to slMes the 
grain of the paper may be got rid of by wetting the 
print or photograph and squeCgeeing it on to Clean 
glass, carefully stroking out the air bubbles between 
the print and the glass. If it is not desirable to wet 
the photograph it may be put in a printing frame 
with glass befoi'e it and then exposed before the 
camera. A line drawing may be copied the same size 
by ooatmg a piece of glass 3iin. by 3Hn. with a. weak 



solution of gelatine. The glass should be placed over the 
design and a tracing made on the gelatine film^with pen 
and ink (Stephens' ebony stain answers well). When yel-y , 
fine lines are required, the film may, be rubbed with 
medium and a retouching pencil used. This tracing can ' 
be used as a lantern plate. The masking, binding, and 
fixing of the cover glass are described above. 

Making Socket Joint In Steam Pipe.— The propor- 
tions for a cement for the socket joint of a steam pipe 
are, by weight, 1 part of powdered sal-ammoniac, 2 parts of 
fiour sulphur, and, 80 to 100 parts of borings ; the borings 
should be pounded it large. These ingredients must be 
well mixed and moistened with water, and will be ready 
tor usein from one to two hours. Cattlk the socket two- 
thirds full of yarn, and finish with one-third of borings. 
The less borings used the better, for a slight expansive 
action occurs in the boritigs when setting, and this 
causes the splitting of sockets; If there are only one or 
twd joints, get some white lead and add sutficient dry 
red lead to make a' stiff putty; thin a little of this wita • 
boiled oil, and paint inside the socket first. Then caulk 
in alternate layers of yarn and putty, commencing 
with the yarn and finishing with the putty. This cement 
is longer in setting than the former one. , 

Stching on Steel.— All processes of steel etching ' 
■ depend on the coating of the steel with a -resist, which 
is scraped away from those, portions to be etched 
or bitten into by chemical action. The resist or 
etching ground is made by melting together over a 
slow fire black pitch, white wax, Burgtindy pitch, 
asphaltum, and gum mastic. Other etching groilnds 
are (1) asphaltum varnish ; (2) yellow beeswax, dissolved , 
in turpentine and continuously , decanted until no 
sediment remains— to 6 parts of this add 1 part bf 
japan varhish; (3) asphaltum, Burgundy pitch, and 
beeswax melted together. The resist may either be 
melted and then brushed on, or the steel may be warmed 
so that on rubbing it with the resist the latter will melt 
and leave, a thin film. The resist is allowed to becolne 
cold and h^rd, and is then drawn on with needles or, 
preferably, with a stick of steel of f-in. diameter round or 
square section tapering to a fine point ateachend; the 
weight of this tool is sufficientto penetrate and remove the 
resist as it is drawn along, thus leaving the hand more 
at liberty to draw freely or form letters as the case may 
be. It the steel is in the form of a plate, it now has a 
Willbf wax built around its edges, and into the shallow 
dish thus formed the etching acid is poured. Knife . 
blades and similar small articles having beeh pro<)erly- 
coated with resist, may be dipped into the acid, or the 
latter may be applied to the portions to be etched by 
means of a camel-hair pencil or a stick, at the end of 
which is mounted a little ball of tissue-paper. Eemember 
that 'all p'drtions not cover-ed with the resist will be 
etched. The etching'acid may be.any of the following mix- 
tures. (1)' Pyroligneous acid, nitric acid, and water ; (2) 
diluted nitrous acid ; (3) 2 oz. of copper sulphate, J oz. of 
alum, ioz. of salt, i pt. of vinegar, and 40 drops of nitric 
acid; (4) 4 pai-ts of glacial acetic acid and 1 pirt of 
^absolute alcohol; allow to remain tor thirty minutes, 
and add" gradually 1 part of nitric acid; (5) 1 part of 
fuming hydrochloric add and 7 parts of water; add 
boiling solution of potassium chlorate and dilute with 
,water. When the acid has bitten sufficiently deep, 
pour it off or remove it, and wash thoroughly in 
clean water. If it is required to etch more deeply certain 
portions, cover up the rest with a stopping ground of 
lampblack and Venice turpentine, or with any of the 
above etching grounds, and apply the acid again. When 
the etching is complete, wash off all traces of acid. 



12 



Cyclopaedia of Mechanics. 



Dyeing Pampas Grass.— To dye pampas grass, place 
it ill fairly strong solutions of aniline dyes, ami heat 
until sufficiently coloured. The most suitable dyes are 
soluble bine, picric acid, fast s'ellow, eosine, magenta, 
methyl violet, malachite green, Bismarck brown, and 
acid brown. If, however, only small quantities are to be 
dyed, use Judson's or other dyes, which may be obtained 
in packets. 

Mltrelng Cornice Moulding.— In marking off the 
ends of two "pieces of cornice moulding which are to be 

i'oined at right angles, the procedure Is as follows, 
iet the section of the moulding be as shown in 
Fig. 1. Draw the plan of the mouldings and mitre as 



perlence, but the following will serve as a guide. Put 
luib. of white lead, Iqt. of raw linseed oil, and about 
i lb. of patent driers in a large pot and mix wejl together, 
adding suftioient black to produce the desired tint. 
Strain through a piece of canvas and add just suiHcient 
turps to make the' paint work smoothly. The quantity 
of driers will vary according to the state of the surface 
to be painted and the quality of the material. The tint 
used must be made to accord with the finishing colour. 
For instance, if a light colour is desired, the priming and 
following coats must be light, so as gradually to lead to 
the finishing tint. For the second coat, the same colour 
may be used as for the first. For the third coat, oxide 
red, linseed oil, and terebine as a drier may be used. 




Fig. 3 



Mltreing Cornice Moulding. 



at Fig. 2. Then set a bevel to the mitre line C D. This 
will be the bevel to apply to the top edge, as indicated 
by the line D (Fig. 3) . For the bevel for the sloping 
back, through the angle at A' (Fig. I) draw A' B'. With A' 
as centre and C as radius, draw the arc C B'. Now draw 
B' B parallel to the lines in the plan, as shown, and C B 
parallel to A' B' ; then join B to A. Set the bevel as indi- 
cated, and apply it to the sloping back of the moulding 
and mark it. .This will give a line as indicated bjr A 
(Fig. 3). As A' E' is a vertical surface, the line A E indi- 
cated at Fig. 3 can be drn.wu square. This principle 
can be applied for mouldirgs meeting at any angle. If 
there are several mitres to be made and all meet at the 
same angle, a simpler plan, and one that will save much 
time, is to construct a mitre box which will hold the 
moulding to the exact angle, as shown at Fig. i, and 
the mitres can be cut in the manner illustrated and 
described on p. 136. 

Fainting Kailway Wagons.— The first or priming 
coat on railwa.y wagons is made of tub white lead, r.aw 
linseed oil, patent driers, a little common black, and 
turpentine. The quantities may bo best judged by ex- 



For the fourth coat, half oxiae paint and half varnish 
may be used. For dead colours, the dry paint Is ground 
In turpentine ; a little gold size and varnish are then 
added and the paint thinned down to a working con- 
sistency with turps. Boiled oil may be used if desired 
with the finishing coats. It is necessary to remember, 
however, that only very small quantities of boiled oil 
should be used if the best results are to be gainedHn 
finishing. Either terebine or gold size may be used as 
driers with delicate tints sucli as would be injured by 
usingp^tent driers. Copal varnish may be mixed with the 
finishing coats, or it may be used by itself as a finishing . 
coat over the last coat of colour. The materials used 
will vary according to the finishing tint. For instance, a 
blue wagon would be finished as follows. The priming 
coat would be lead colour, rather dark, as described 
above i the second coat would be the same with a little 
blue mixed in ; t bird coat, ultramarine or Prussian blue 
as a dead colour i fourth coat, the same, with halt its 
bulk of varnish. The writing and picking out would 
then be put on with two coats of dead colour, the last 
coat being clear varnish. The usual practice is simply 
to paint with three coats of lead colour. 



Cyclopaedia of Mechanics. 



13 



Blackening Aluminium.— The troiize known in tho 
trade as " arsenic bronze," diluted with an equal ciuan- 
tlty ot water, is used for ■blackening aluminium. 
First the exposed parts ot the surface should be curled, 
not straigHt-grained, with emery-paper ; then the metal 
should be qiiickly dipped into the fluid and as sharply 
withdrawn, and drained. If on the first immersion the 
bronze has not taken well all oyer, the process should be 
repeated. If the preparation is too strong, there is a 
danger that tie acid will eat away the metal. A 
recipe for arsenic bronze is hydrochloric acid, 121b.; 
sulphate of iron, lib. ; pure white arsenic, lib. To this, 
for aluminium, must be added an equal quantity of 
water; and, when the metal has blackened, it should 
be dried in a mixture of blacklead and sawdust. Only 
-sufficient sawdust is required to soak up the moisture. 
The exposed parts then may be lacquered. 

Elliptical Headed Door Frame.— In commencing to 
set out and construct an elliptical headed door frame, 
^idth 5 ft. 6 in., rise 1ft. 3 in. inside measurement, to 
be made in two thicknesses of 24-in. and ii'-in. stuit screwed 
together, first set out the head full size on a board as 
shown in Fig. 1. A mould should be made for half the 
inside thickness, and one for the outer thickness ; from 
these moulds the stuff should be marked out. It will be 



For pink, add to a solution of cobalt nitrate or cobalt 
chloride sufficient sesquiearbonate ot ammonia to dissolve 
the precipitate first formed. Porjiurpte, (a) mix a solution 
of 2 dr. of sulphate of copper in 2 oz. of water with a 
solution of 1 dr. ot French gelatine in 2 oz. of boiling 
water, "land add 2pt. ot liquor of potassa; shake a tew 
times during ten hours, decant, and dilute with water ; 
(6) dissolTe 1 oz. of copper sulphate in 1 ijt. of water, and 
add lioz. of sesquiearbonate of ammonia: (c), add sulli- 
cient carbonate of ammonia to an infusion of logwood ; 
((J) dissolve 3 oz. of lead acetate and Idr. of cochineal in 
sufficient water; or (e) add sulphate of indigo, nearly 
neutralised with chalk, to an infusion of cochineal. For 
red, (a) dissolve 10 gr. of sulphoeyanide of potassium to 
1 gal. ot water, and add 10 drops of a solution ot per- 
chloride of iron ; (b) dissolve carmine in ammonia and 
dilute with water; (c) dissolve cochineal in a weak 
solution ot ammonia ; (cJ) dissolve madder lake in sesqui- 
earbonate of ammonia and dilute with water ; or (e) dis- 
solve cochineal in sal-ammoniac and dilute with water. 
For violet, mix together solutions of nitrate of cobalt 
and sesquiearbonate of ammonia, and add sufficient 
ammonio-sulphate of copper. For yellow, (a) dissolve 
,11b. of sesquioxide of iron in 2qt. of hydrochloric acid, 
' and dilute with water ; (b) add a little alum to a strong 
decoction of French berries; (c) dissolve either the 




seen from the drawing that the outer part ot tfte head 
is made of three pieces— that is, from A to B, B to C, and 
C to D ; the inside is constructed of four pieces— from A 
to E, E to P, F to G, and G to B. The dii-eotiou of the 
grain for the outside pieces is indicated in the illustra- 
tions. The connection between the head pieces and the 
posts is fully shown by Figs. 2 to 5, as also the general 
construction of the head. It will be a stronger job if 
the pieces are glued as tyell as screwed together. 

Chemists' SUow Bottles. — For an amber-coloured 
liquid for use in chemists' show bottles, dissolve 1 
part of coarsely powdered dragon's blood in i parts 
of oil of vitriol, and dilute with cold distilled water. 
Blue liquid may be a diluted solution of (a) 1 oz. of 
copper sulphate in i oz. of sulphuric acid, (b) soluble 
Prussian blue in oxalic acid, or (c) indigo in sul- 
phuric acid. Crimson liquid is a diluted solution of 
30 gr. each ot iodide of potash and iodine in 1 dr. of 
water; or an infusion ot 1 oz. of alkanet root in 20 oz. 
of turpentine. For green, (a) dissolve 1 dr. ot copper 
sulphate and 30 gr. or bichromate of potash in 2 oz. ot 
liquid ammonia, and add 1 gal. ot water; (b) dissolve 
2 oz. of copper sulphate and 4 oz. of sodium chloride in 
1 pt. of water ;- (c) dissolve distilled verdigris in. acetic 
acid and dilute with water ; or (d) dissolve blue vitriol 
in water and add nitric acid until ot the right tint. For 
magenta, dissolve acetate ot rosaniliue in water. Orange- 
coloured liquid is (a) a solution of bichromate of potash 
in water io which is then added a little sulphuric acid, 
or (b) a dmits solution of gamboge in liquor of potassa. 



chromate or bichromate of potassium in water; or. (d) 
dissolve, equal parts of nitre and potassium chroinate, 
in water. Multi-coloured or variegated show bottles are 
formed by employing a number ot liquids liavmg 
different speoiflo gravities and different colours. Pour 
in the following solutions in the order mentioned, using 
a funnel and allowing the stream to fall upon a fioating 
cork. (1) Chemically pure sulphuric acid tinted blue 
with indigo sulphate, (2) chemically pure and untirited 
chloroform, (3) glycerine tinted brown with caramel 
(burnt sugar), (4) castor oil tinted red with alkanet root, 

(5) 40 per cent, alcohol tinted green with aniline colour, 

(6) cod liver oil containing 1 per cent, of oil ot turiien- 
tine, and (7) 94 per cent, alcohol tinted with aniline 

_ violet. 

Precautions in Making White French Polish.— 

To protect the shellac, from atmospheric influences it 
should," when at the merchant's, be stored in water; 
neglect of this precaution causes the shellac to lose its 
nature, and it will not then dissolve by simple immer- 
sion. The lac, when purchased, should be at once broken 
up small, spread on clean paper, and set aside in a warm, 
not hot, place, and frequently turned over till it feiels 
quite dry. It should then be placed with the spirit in a 
stone or earthenware pickle .iar, over the top of which a 
piece of rag should be tied. Then set the jar in a sauce- 
pan partly filled with water, glue-pot fashion, and place 
in an oven or on a gas or oil stove, and gradually bring 
up to blood heat. If tbe iajp does not then dissolve, it 
should be thrown away as worthless. 



14 



Cyclopaedia of Mechanics. 



Polishing Curling Stones.— Ab a rule, curling stones 
are made oi granite or ti-ap, a ihixture of felepar and 
hornblende ; therefore to polish them without machinery 
is very laborious work. Rig up a vertical lathe similar 
to those used by lapidaries, and place the stone on it, 
and, while revolving, put coarse emery and water on It, 
pressing a piece of smooth iron on the stone as it 
revolves. When all pits and unevennesses are removed, 
carefully wash away the emery grains and go through 
the same process with fine emery, removing all scratches 
left by the former treatment. This process must be gone 
through with care, as if scratches are not removed it 
will be impossible to get a good polish. When an even 
grain, dull polish is obtained, carefully wash again, 
removing all traces of emery. Fasten a piece of felt to 
a piece of wood and on it put some putty powder slightly 
wetted, and apply to the stone until a good polish is 
obtained. A deal of the rough work might be done in 
bringing the stones into condition for further grinding 
if In the first instance they could be slung in front of a 
grindstone. 

Vignetting Photographs.— If It is required to make 
a vignette photograph without showing much dai'k 
around the head and neck proceed thus. Cut in 
cardboard (old plate boxes answer well) a vignette con^ 
siderably smaller than the desii-ed vignette & (Figs. 1 and 
2), and fix about J in. from the negative by fastening with 
drawing pins. To do this, it may be necessary to nail 
some strips of wood B around the outer edges of the 
printing frame. Fig. 1 shows a perspective view and 



it on a piece of boxwood, file it to a gentle taper until tha 
end just enters the hole in a screw-plate j the wire may 
then be screwed into the latter, plenty of oil bein^ 
used. When it goes hard,' turn it back, halt a turn, 
then forward three-quarters of a turn, back half a 
turn again, and so on, advancing slowly until a full 
thread is cut for a sufllcient distance. The,n file three 
flats upon it for the whole length of the thread, taperlhg 
the flats to the end, where they should meet in, a knife 
edge and show only half a full thread. Harden the 
tap by heating to a red colour and plunging in cold water. 
Brighten one flat and heat it over a flame until it is of a 
pale straw colour. This renders it lessbrittle, and is called 
"tempering." Then carefully smooth all three flats on 
an oilstone so as to leave good cutting edges. Finally, 
file some nicks in the soft end to indicate the number or 
the hole in the screw-plate to which it belongs. 

Making a Wcod Chuck In Sections.- A section chuck 
in wood, suitable for spinning a silver jug In the lathe, 
may be made in this way,. Fix a piece of hornbeam of the 
requisite size on the mandrel and turn it to the shape of 
Fig. 1; AB is the height of the jug, Op the diameter at its 



|q 



B- 




$m 


E>r 




1 A 


;$ 


P! 


i 




A 


;^\' 


1 


i^l 


^'^f 





Fig. I B f^iG 2 

Vignetting Photographs. 




Making a Wood Chuck In Sections. 



Fig. 2 a section of the Vignetted frame. Cover with 
cotton-wool A any thin portions of the negative coming 
near the margins— such as may occur with a black coat- 
or the light will creep too far and the shape of the vig- 
nette be spoilt. The wool must be pulled out very loose 
and soft, or a hard line will be shown by the shadow it 
casts on thS negative. In cases where the negative Is 
rery thin it is advisable to cover the vignette with tissue 
paper. Vignettes should always be printed in subdued 
light. A vignette card must not be cut too closeiy 
around the figure, nor its outline repeated too decidedly, 
as the effect thus obtained will be quite as inartistic as 
the stereotyped egg shaped pateta. To produce a success- 
lul vignette, a light background must be used. With a 
dark background it is all but impossible to get a soft 
vignette. The farther the hole is from the plate and the 
darker the background of the negative, the larger will 
the vignette be, and the softer will be its outline. During 
early attempts 8,t vignetting the print should be examined 
from time to time to see that the vignette is going on 
satisfactorily. 

Straightening Brass Curtain Poles.- '^o straighten 
a brass curtain pole that has been used for a bay window, 
first anneal the tube where bent, then load it with lead 
and, alter cooling, pass it through a hole in a firmly 
fixed bench until the shoulder of the bend rests against 
the shoulder of the hole. Then pull the tube until it is 
quite straight against the wood shoulder. Finally^melt 
out the lead and repolish and lacquer the tube. When 
lacquering the tube, first gently heat it, then apply 
with a brush lan even coat of lacquer, and stand it 
aside free from dust until dry. 

Making Taps for Watch Screw Threads.— Taps for 

watch screw threads may- be made from needles, but 
prcbd,bly they would not last long. A tap should be made 
from the best steel ; therefore get a length of tool steel 
wire of the correct size. From this cut off a suitable 
length, say IJ in. Soften it by heating to a dull red and 
allowing it to cool slowly. Hold it in a pin- vice and, resting 



narrowest point, and A C the profile of its upper part. The, 
diameter of the long cylindrical part C B should be as 
large as possible without weakening the chuck. Next join 
a number of wedge-shaped pieces of hornbeam, as shown 
in Fig. 2 ; one of the wedges marked 1 should be so shaped 
that its broadest part turns away fi'om the outside, 
while the opposite is the case with the other wedges. 
The joints must be perfect, and are best finished on their 
joining surfaces with a toothed plane, being so glued 
together that a piece of brown paper is inserted between 
each p^r of wooden surfaces. Joip 1, 2, 3, 4, and 5 together ; 
next 6, 7, 8, and 9. It jvill now be seen that if the free 
surfaces of 1 and 5, and 6 and 9, are lying in one plane, 
the last joining will be fairly easy to accomplish. The 
better plan is to make a drawing, plan down the shape 
of the wedges, and work accordingly. When all are 
joined and dry, chuck the roughly cylindrical pieces 
bore it out, and turn a ring on one end which will fit 
nicely in the annular recess shown at D (Fig. 11, the 
cylindrical pa.rt B fitting tightly in the hole bored 
without forcing the wedges from one another. When 
this is accomplished, the chuck can be finished to tem- 
plate as Fig. 3. Now separate the wedges, first marking 
them with lead pencil so as to secure their proper posi- 
tions. Eemove the loose part of the chuck, insert a thin 
knife blade in any of the glued joints, and tap gently 
with a mallet on the back of the knife. The wedges, 
owing to the brown paper inserted between them, can 
easily be separated ; tuese nine wedges, when placed on 
the fixed part of the chuck in their proper -rotation, will 
appear like one single piece. When the metal has been 
spun home and is removed from the lathe, it is evident 
that all the wedges are inside the bowl of the jug ; but 
when this is released from the fixed part of the chuck, 
piece 1 (Fig. 2) can be pushed towai'ds the centre and 
drops out, the, other pieces following. Take care 
that none of, the wedges are of larger transverse 
dimensions than will permit of them passing easily 
through the narrowest part of the jug's neck i a 
drawing of the sections should be made before joining 
them together. 



Cyclopaedia of Mechanics. 



15 



Determining Grate Area, etc., of Vertical Boilers. 

—To determine the grate area of a vei-tical boiler, 
take the diataeter of the firebox at the bottom of 
the firehole and obtain the area. For instance, in a 
boiler 6tt. 6in. high by 3ft. diameter, the firebox at 
the bottom Is 2 ft. 5i in-. At the firebar level, how- 
ever, this diameter is about li in. less, viz. 2 ft. i in. 
The area of circle of this diameter = 615-75 sq. in. = 
4-27 sq.. ft., which is the area of the grate. To obtain 
the approximate heating surface, multiply the grate 
area by 10, the ratio of heating surface to grate sur- 
face in these boilers being about 10 to 1. Thus, the 
heating surface in the boiler in question = 4'27 x 10 = 
42'7 sq.ft. An approximate rule for the horse-power is 
to allow 10 sq. ft. of heating surface.per horse-power. 

Cutting Figured Boards from Fltch-pine Logs.— 

Some hints are given here on sawing up a pitch-pine log 

so as to get the best variety in the figuring of wood to 

be used for panels. It must be remembei-ed that the 

amount of figure in .a pitch-pine log depends on 

the amount of irregularity of growth in the 

ti-ee. Curly figured pitch-pine cannot be 

got out of a plain pitch-pine log. But even fii b 

the plainest log will afford a good amount 

of passable figure with judicious handling. «5 
In the accompanying illustrations, which ' 
treat only of plain logs, the outer board A ( 
(Pig. 1> will have a large and open figure, 
approximating to the type shown in Fig. 4, 
and BO also would the outer boards on the 
three other sides of the same log. From A 
to B the figure narrows down considerably 



it is lost altogether, the board E being shown in Fie. 6. 
The reverses of figure shown at I, J, and K (Fig. 5) are 
due to slight bends that occurred in the growing tree— 
the saw, m its straight course, revealing outcrops of 
lower layers of wood. The figure on any, given side of a 
log may also be varied within certain limits by first 
cutting a long wedge-ehaped slaji off the side and then 
making all subsequent boards parallel (in thickness) to 
the newly exposed surface. Closeness of ring will also 
affect the figui-e to some extent ; but these circumstances 
do not interfere with the general principle just given. 

Recipes for Bottle capping Mixtures or Waxes. 

—The following recipes are for waxes and mixtures 
for use in sealing bottles. (1) Soak 7 lb. of good gelatine 
in 10 oz. of glycerine and 60 oz. of water and heat over a 
water bath until dissolved ;,the'mixture can be coloured 
by the addition of pigments, and various tints can be 
obtained by the use of aniline colours. The resulting 
compound should be stored in jars. To apply, heat 
the mass to a liquid and dip in it the cork and 
, portions of the neck of the bottle ; it sets 
very quickly. (2) Mix 1 oz. of gelatine, 1 oz. 

of gum arable, and 20 gr. of boric acid -with 

14 fluid oz. of cold water. Stir occasionally 

until the gum is dissolved. Heat the mixture 

to boiling point, remove the scum, and 

strain. Then stir in a mixture of 1 oz. of 

N starch and 2 fluid oz. of water until a uniform 

' , - product results. As in the former recipe, 

the composition may be tinted with any 

suitable dye. Before using it must be 

softened by the application of heat. (3) 



Fig. I 




FIG. 2 





Fig. 3 



Fig. 6 
Cutting Figured Boards from Fitch-pine Logs. 



until when the position B is reached the amount 
and proportion of the figure will be approximately 
as shown in Pig.. 5. The figure in all the boards 
vrill be symmetrical— that is to say, its climax, or 
turning point, will be at the centre of every board. All 
wi^l, therefore, be suitable for panels. The symmetry of 
figure is due to the position of each board, relatively to 
the annual rings of the log. Each board is tangentially 
situated, the point of contact being near the centre of 
its width. Thus, the board C (Pig. 1) , while inclined at a 
different angle to the boards A and B, will still have the 
same kind of figure on its faee^for the reason that it is 
situated tangentially to the rings. Boards cut on the radii 
of the tree, as D and E (Pig. 2), will have no fiower figure, 
and except for the presence of an occasional knot or two, 
perhaps, will have little of an ornamental chai-acter on 
their sm-laces, excepting, of course, the straight or wavy 
lines t];iat represent the edges of the yearly layers of 
wood (see Fig. 6). Here again the board J (Pig.^) is dis- 
posed diagonally to D and E, but the figures will be the 
same, for all are situated on radii of the tree. To secure 
the greatest amount of figure out of any given log, it is 
therefore necessary to cut as many boards as possible 
tangentially to the rings. In Pig. 3, for example, each 
board will be ornamentally figured, and the width of the 
figure will be proportionate to the -width of the board 
throughout. It is unfortunate that ip securing this 
result the boards will vary so greatjy in width. The sketch 
is given here only as an extreme example of a means to , 
an end. In Pig. 2 the boards G and H are practically 
halves of theboard A (Pig. I), and the figure in these will 
therefoie be like the upper and lower half respectively 
of the board shown in Fig. 4. Prom G and H, in towards E, 
the figure at th« inner edges of the intermediate boards 
becomes less and less prominent, until when E is reached 



Dissolve 3 oz. of shellac, IJ bz. of -Venice turpentine, 
and 72 gr. of boric acid in a mixtm-e of 12i fiuid oz. of 
alcohol and 6 fiuid drachms of ether, colour with a 
spirit-soluble dye, and add 3oz. of powdered talcum. 
During use the 'mixture must be agitated frequently. 
(4) For a black bottle wax, melt together equal parts of 
common resin, pitch,, and ivory black. (5) Another, melt 
together 201b. of eOmmon resin, 51b. of tallow, and 41b. 
Of lampblack. (6) For a red bottle wax, mix together by 
the aid of heat 151b. of common resin, 41b. of tallow, 
and 5 lb. of red lead. (7) Melt together 6oz. of resin, ' 
2 oz. of shellac, and 2 oz. of -Venice turpentine, and add 
9 oz. of lampblack or other colouring matter. (8) Bed : 
Melt together 6i parts of resin, i part of beeswax, and 
li parts of -Venetian red or red lead. (9) Eed ; Use 4 oz. of 
shellac, 1 oz. Venetian turpentine, and 3 oz. vermilion. 
Melt the laC in a copper pan suspended over a clear 
charcoal fire, and pour the Venice turpentine slowly into 
it, finally adding the vermilion, stirring briskly the whUe. 
(10) Melt 21b. of shellac and 41b. of resin cautiously in 
a bright copper pan over a clear charcoal fire. -When 
melted, add 2ilb. of Venice turpentine and IJlb. of red- 
lead. Pour into moulds, or form sticks on a warm marble 
plate. Gloss may be produced by polishing the sticks 
with a rag until they are cold. (11) The following recipe 
is recommended by Shelrer ; Heat 2 parts of Burgundy 
pitch until all the water is driven off, add 1 part of tur- 
pentine and 4 parts of colophony, and when the whole is 
liquid thoroughly -mix it -n-ith 2 parts of chalk, i part of 
carbonate of'magnesia, and ^ parts of Armenian bole. 

Making Coloured Crayons.— Coloured crayons may 
be made by mixing pipeclay with water to form a stiff 
dough. The material may be made harder by adding a 
little soap to the water. For a blue coloui-, add common 



16 



Cyclopaedia of Mechanics. 



ultramarine ; for red, use Venetian red ; tor brown, use 
limber or vandyiie brown ; and for blacli, iise larapblaolt. 
After standing two or three days it may be made into 
balls, rolled into rods between two boards, then cut up 
into lengths and dried, first in the air and finally in a 
warm place. 

Trap or Tub for 13-Hands Pony.— Pig. 1 is a sida 
elevation and Tie. 2 a back elevation drawn to a scale of 
I in. to 1 ft. of a tub or trap suitable for a 13-hauds pony. 
The length on the seat is 3ft. 3 in. ; length of top rail, 
3 ft. 9 in. ; depth of well, 11 in. ; depth above seat, 9 In. ; 
length of bottom, 2ft. 6 in. ; width, 2ft. ajin, Greater 
sail is given to the sides so that the top of the vehicle is 
quite square. "Walnut should be used for the well if to 
be finished in plain varnish. If the frame bottom be of 
ash, a pair of fence routers for rabbeting on sides and 
bottom will be required. Or the trap can be put together 
by rabbeting the ends and using 1-in. deal boards for the 
bottom, which can be nailed to battens running along 
the bottom of the sides. The seat boards are of birch 
12 in. wide, screwed on top of the well ; or the seats may 
be all framed together similar to the bottom. The four 
corner pillars andtop railsare liin. by li in. The sticks 
are of ash, ^ in. sqiiare, finished black, the stained 
mahogany panels being screwed on inside. The wheels 
are 3 ft. 6 in. ; stocks, 6i in. diameter by 7 in. long. Front 
hoop, 4 in. Inside diameter by 2 in. wide ; hind hoop, 5 in. 
diameter by 1 in. -wide ; spokes, H in. ; felloes (cut from 
2-in. ash plank) to finish about H in. square on thickest 
part ; tyres, IJ in wide. The wings are 3 ft. 1 in. by 6i in. 



the charge la too strongly heated the vessel might be 

Eierced ; If there appears a likelihood of the latter 
appening, add a quantit.y of cold saltpetre or withdraw 
the fire. Continue stirring after the lead has been 
added, and then, by means of a Iffrge cast-iron ladle, run 
the melted mass into cold water and assist the solution 
by constant stirring. The decomposition of the salt- 
petre by the lead at from 420° 0. to 600° C. produces,' 
besides the nitrite, about 1 per cent, of caustic soda, 
which dissolves some of the oxide of lead formed; to 
remove the latter, neutralise the solution with nitric 
acid. In this manner saltpetre is re-formed, the oxide of 
lead being pi-eclpitated as insoluble hydroxide. The 
neutralising maybe effected either with nitrate of lead 
or with dilute sulphuric acid instead of nitric acid; 
of the two former, sulphuric acid is the cheaper, but by 
its use sulphate of soda is deposited in the concen- 
trating vessels in the form of anhydrous salt. There 
are now in aqueous solution (1) nitrite, (2) unde- 
composed saltpetre, (3) caustic soda holding oxide of 
lead in solution, and (4) the soluble impurities of the 
saltpetre, such as chloride of sodium, etc. The insoluble 
residue which was pr'ecipitated consists of (1) oxide of 
lead, (2) a very small quantity of metallic lead which has 
escaped oxidation, and (3) peroxide of lead. The solution, 
diluted to from 6° B. to 8° B., is neuti-alised again with 
the same agent as was used before ; the oxide of lead in 
solution Is precipitated, and the neutralising agent is 
added as long as a precipitate will form. It may here be 
mentioned that it is commonly supposed, and most 
authors state, that nitrite of sodium has an alkaline 




Trap for 13-Hands Pony. 



by i in., and the raised backs 3 ft. 1 in. by 4 in. by 1 in. 
The wing irons should be fastened on underneath raised 
backs, and have 7 in. clearance of the wheels. Tlie 
elliptic springs are 3 ft. I in. between centres of eyes and 
have five plates li in. wide. The shafts are fastened 
under the seats, and are 5 ft. 5 in. long in front of 
splinter bar, and 21 in. to 22 in. wide where the tug stops 
come about 15 in. from points. Breeching staples are 
2 ft. frt>m splinter bar, wlaich is IS in. wide by li in. deep, 
and let on tops of shafts | in., clearing the front of the 
trap by an inch or so. The dash is 21 in. long and 12 in. 
high ; axle, li in. at least with a 5-in. crank, and 3 ft. 7 in. 
between shoulders, clearing bottom of tub 9 in. The 
step is lOJ in. long, 6 in. wide, and 6 in. broad. The 
door handle is of Sj-in. plain brass. The door is 17 in. 
wide at the top and 15 in. at the bottom. 

Tlie Manufacture of Nitrite of Soda.— The value of 
nitrite of soda in the improved methods of dyeing fabrics 
is increasing. Below is given a brief but authentic 
account of the manufacture of that chemical. The 
raw material, from which nitrite of soda is manu- 
factured, is purified Chile saltpetre ; the sodic chloride 
present in the latter lowers the value of the nitrite, but 
the elimination of the sodic chloride is an expensive 
operation not generally practised. The saltpetre is 
melted in large cast-iron vessels, and this involves the 
evaporation of the water and the decomposition 
of a part of the iodides and iodates which are in the 
saltpetre. The lead necessary for the decomposition 
of the saltpetre must be pure, as the presence of small 
quantities of other metals, especially of antimony, 
might cause the decrepitation of the whole charge. 
When the saltpetre, which melts at 310° C, has reached a 
temperature of 420° C, 14 parts of sheet lead are gradu- 
ally added foj' every 5 parts of saltpetre, the whole being 
constantly stirred to obtain an intimate mixture. If 



reaction, but this is not the case, the pure nitrite being 
absolutely neutral. The neutralised solution is separ- 
ated from the insoluble precipitate by any conven^nt 
method, and is then concentrated in oast-iron pans until 
it has a density of from 42° B. to 45° B. when warm. 
The insoluble precipitated residue is thrown upon a 
large filter of coarse sacking, where it is washed with warm 
water and the wash waters are added to the principal 
solution. The concentrated solutions are mixed together 
in cast-iron vats and left to crystallise ; if the crystals 
thus obtained are not pure, they must be re-dissolved 
and re-crystallised. The pure crystals are separated in 
a centrifugal machine, washed, and dried. The desic- 
cation takes place in an oven at a temperature of about 
50° C, andlthe crystals are packed in parchment-paper 
cylinders of double thickness. The residuary oxide of 
lead may be melted and east as it is, reduced to the 
metallic state, or transformed into minium, a heavy, 
brilliant red pigment which is used as a cement and 
paint, and in the manufacture of flint glass. The lead 
oxide can also be used in the preparation of white lead, 
of lead nitrate, lead acetate, and other plumbic com- 
pounds. 

How to Produce Red Letters on Glass. — Ked 

letters are produced on glass by a sand-blast process. 
The glass used for this ijurpose is known as ruby 
flashed glass. The letters that are to be produced are 
first cut out in paper. These paper letters are coated with 
a resist or protective covering composed of 1 part of 
ordinary hot glue and 1 part of glycerine, mixed together. 
The letters are then pasted on the glass, the resist 
side outwards, and the glass is then ready for blasting. 
The sand cuts away the unprotected surface of the glass, 
the resist protects the paper letters, and, when these are 
washed on the glass, red transparent letters will be 
shown on a white opaque ground. 



Cyclopaedia of Mechanics. 



17 



Preparing Tannic Acid. — An impure tannic acid 
may be obtained Irom mjrobalans (a dried astringent 
fruit resetobling a prune) by grinding them and 
extracting in a boiler containing hot waters the 
liquid may be strained and evaporated to dryness, 
yielding a dry extract which is suitable for dyeing 
or tanning purposes. A concentrated fluid extract is 
often made by partial eTaporatioii. To obtain a pure 
tannic acid, it would be necessary to treat the myro- 
balans in the same way as nutgalls, i.e. extract by per- 
colating a mbcture of alcohol and ether through the 
\ powder. The percolate will separate Into two layers; 
I the lower one is a watery layer containing the tannin, 
' the upper layer contains the alcohol and ether, with 
colouring matter, etc. The alcohol and ether can be 
recovered largely by distillation ; the watery layer is 
evaporated to dryness, and yields the pure acid. 

Removing Stains from Linen.— Tea and fruit stains 
are removed from linen by steeping the latter in a 
chloride of lime solution (about \Vo. to Igal. of water), 
or preferably in hypochlorite of soda,' which may be 
made by treating i lb. of chloride of lime with i gal. of 
water, dissolving |lb. of washing soda in igal. of water, 
and mixing the two solutions. The solution should be 
allowed to remain till clear, the liquid, which Is poured 
off from the deposit, being used for bleaching. 

Making French Cork Boot.— In fitting the second in- 
sole of a French coVk boot where a box and rand are sewn 
in, last the boot in the ordinary way, taking care that 
the feather is nice and even, and thattheire is a good 
innersole to work upon. For the box, apiece of first cut is 
cut the required length, say from lain, to Win., and 
about Jin. wide. Mark a line, as AB (Fig. 1), on the 
grain side of the leather, i in. from the edge, and cut it 
thitough a little way, then serve the reverse side in a 
similar manner, as at C. The leather should be damped, 
and the cuts made larger with a channel opener, a welt 
plough or knife being used to cut a thin strip of grain from 



another filling. Make this with 2 parts of linseed oil and 
1 part of turpentine, and add a tablespoonful of sugar of 
lead or of sulphate of copper driers to every pint of 
filling i the lead does hot affect the colour of the filling 
so much as the sulphate of copper. Wipe with rag as 
before, and allow to stand for a day or two. If the 
weather makes the oil sweat out on the surface, wipe it 
thoroughly dry and then well brush on a light coat of 
pale copal varnish, following in a day, or two with a 
finishing coat of hai-d-drying copal varnish; The surface 
of the first coat of varnish may be rubbed over with a 
bunch of clean horsehair to remove nibs and to grain it 
slightly; this dnlness favours absorption of the next 
coat of varnish, which is a full flowing coat liglitly laid 
on. Among the points it is necessary to remember are 
these. Do not let the varnish flow into recesses ; let 
there be at all parts only the amount of varnish laid on 
with the brupn ; and always hold a small dry tool in the 
, left hand with which to wipe off superfluous varnish. 
The ironwork, if quite bright, may be varnished with 
carriage copal varnish in which a little white lead, 
thinned with turpentine, has been mixed (a tablespoon- 
ful to 1 pt. of varnish) . The ironwork must be free from 
grease or oil before it is varnished, or it will dry un- 
evenly. Black japan Is used for common work such as 
Ealli cars, but it does not harmonise with other colours. 
Leather, if used for dash-iron or wings, should be red- 
tan enamelled, or japan surface leather should be used ; 
either of the leathers mentioned is more snitahle than 
black leather for the purpose. 

Gypsum, or Plaster-of-Parl?. — Plaster-ot-Paris, or 
gypsum, is a sulphate of lime found at places in 
Cheshire, Cumberland, Derbyshire, and Oxfordshire, 
In England, and at many places in the neighbour- 
hood of Paris, Prance, hence one of the names given 





Fig. I 



FIG. 2 F'Q- 3 

Making French Cork Boot. 



the narrow side as at D. Or the box can be worked 
with one bevel edge (see E, Pig. 2). Instead of sewing in 
a welt, the box can be sewn in, and in doing this the awl 
will go in at A (Pig. 1) and come out at C. The piece taken 
out at D will admit of the box lying close to the upper, 
while the channel at C allows the stitch to sink in. If a 
box like Pig. 2 is used, the awl should go in at the dotted 
line on the bevel edge E and come out at P. This is also 
shown by the dotted lines G and H in Pig. 3, which is a 
transverse section of nearly the whole of the middle 
portion of the boot. Thus the awl goes in the innersole 

•at J just as for a welt. When the box Is sewn in all 
round, it can be gently hammered down, trimmed, and 
ironed up, as shown by the dotted line K. The welt; as 

, shown at L (Pig. 3), is sewn in as follows :— Starting at 
the heel, sew up the waist to where it meets the box. 
Between these stitches put the awl under each loop, 
letting it grip the Innersole and come out on the top of 
the box, thus sewing in the welt, and on to this the sole 
will be stitchied asatM, N. A very thin layer of felt is 
put in, and the remainder filled up with sheet cork, 
excepting another thin layer of felt to keep the boot 
from creaking when the outer sole is put on. 

Vamlsliing a Carriage In the Wood.— It is assumed 
that the vehicle to be varnished is made of four-diiferently 
coloured woods— ash, creamy white ; mahogany, reddisb 
brown ; hickory, flesh-coloured drab ; and lancewood, 
straw colour. The straw colour of lancewood contrasts 
best with mahogany, so thetwo other light-coloured woods 
have to be tinted to match straw colour. Por this pur- 
pose coat with a solution of gamboge and turpentine, a 
few drops of linseed oil being added to every pint of the 
stain; test on any odd bits of a^h and hickory to make 
sure the stain is of therlghttint. Prepared yellow stains 
might be diluted to answer the purpose. The staining does 
awaywith the patchwork look of the severallight-oolonred 
Woods. The next process is to fill the wood grain. The 
dense lancewood will not need so much filling as the other 
woods. Ihe filling is a nearly colourless liquid made by 
mixing together 2parts of turpentine and 1 part of palest 
linseed oil ; apply it with a stumpy-haired brush, and 
wipe off any superfluity with a clean white rag, rubbing 
the latter well into the wood to smooth the grain which 
the liquid filling has raised. After a day or so, brush in 



to it. It is also found in (xermany,~Switzerland, Italy, 
Spain, and North America. According to Burnell, it 
occurs " either in contemporary strata of great thick- 
ness (as near Paris) in the tertiary formations ; or in the 
iridescent marls of La Meuse, or the Aveyron ; or in 
masses of a subsequent date in ditterent secondary 
rocks." The latter kind, being generally in contact with 
igneous rocks, is associated frequently with the dolo- • 
mites, rocksalt, bitumen, and sulphur. The better 
qualities of gypsum have almost the hardness of cal- 
careous stones, but after the evaporation of the water ' 
of crystallisation by burning they are easily powdered. 
On being moistened with water gypsum reassumes the 
hydrate form it possessed before it was burnt, and it 
crystallises on and around the substances between which 
it is placed, recovering its original density and strength. 
It is for this reason that gypsum is so extensively used 
in building. Gypsum is quarried underground and in the 
otien either by cuttitig with picks and wedges or by blast- 
ing yyith explosives. The gypsum stone is broken up fairly 
fine and conveyed to the kilns, which are primitive struc- 
tures, consisting of three brick walls supporting a tiled 
roof in which are openings to allow the escape rif 
steam ; one side of the kiln, which really is but a shed, 
is open. The gypsum is piled up in the form of arches, 
the larger stones being at the bottom, near the fireplace 
formed by the vaults of the arches. In the latter a 
wood fire is lighted, the flames rising through the 
crevices left between the stones. A greater heat than 
2(J0°G. over-calcines the gypsum, which then loses its 
power-of combining with the water and reassuming its 
hydrous sulphate form, A better kiln than the shed 
form is that with its chimney passing round and round 
■ the gypsum, which thus does not come in contact with 
the smoke or fuel ; the latter in the ruder form of kiln 
discolours the calcined article. Perhaps a still better 
method is the one in which advantage is taken of the 
fact that steam at very high temperatures is a gas 
possessing great aflinity for water. The finely broken 
gypsum is subjected to the action of steam of the tem- 
perature of 205" C, and a pure anhydrous sulphate of 
lime is produced. The calcined gypsum is powdered in 
a mill, and is then ready for use.^lt is necessary to pack 
it very carefully, as in contact with a damp atmosphere 
it will rapidly spoil. 



18 



Cyclopaedia of Mechanics. 



Keclpcs for Pottery Glaze.— Different clays have 
different shrinkage, require different firing, or stand 
a greater or less degree of temperature, hence the 
glaze is a matter of trial. Glazes are coloured by admix- 
ture of small quantities of metallic oxides. Common 
clay vessels are painted over with red-lead, hut this glaze 
is dangerous, as it is affected by acids. Borax will make a 
glaze, and is used as a ilux. A white earthenware glaze 
may be made from Cornish stone 35 parts, borax 20, 
crystals of soda 10, red-lead 20, and blue calx i part. 
Calcine and pulverise and grind with 20 lb. of white-lead, 
101b. of Cornish stone, and 51b. of flint. 

How to Make a Silent Camera Shutter.— A noiseless 
shutter that worlts inside the camera and that will 
glTe any length of exposure is ' made as described 
below. Being perfectly noiseless, they are particu- 
larly suitable when photographing children and 
anim;i,ls. Exposixres as brief as a quarter of a second 
may be giyen, which is generally sufficiently quick for 
such work. Construct a box A (Fig. 1) of the dimen- 
sions shown, dividing it lin. from the end with a strip 
of the same width B, having a slot C. Through this slot 
and also the holes D and E previously made in the frame- 
work a roller r, about i m. in diameter, is passed (a 
wooden knitting-needle answers well). In this roller 
burn two holes 3iin. apart, and into them fix the wire 
frame shown in Fig. 2 so that it hangs flat. Now cover 
rod and frame with thin velvet, gluing to the rod and 
sewing over the frame. Hake a frame 4 in, wide and 
1* in. deep to fit the left-hand eompai-tment, as shown by 
dotted lines. This frame is afterwards covered on its 
inner edge with velvet, making a light-tight join. Around 
the I'Ollei* F glue one end of a strip of tape, 2in. long, and 
wind the remainder around free, joining the loose end to 
a strip of wood G, about 3 in. long. G is hinged to the 
bottom iyith a small piece of tape also. Next wind some 




Fig 3 

How to Make a SUent Camera Shutter. 

fine wire around a small rod to form the spring H, and 
fasten to this roller and the side of the framework as 
shown. If now the strip G is forced down, the roller is 
pulled round and the flap opens, but is pulled back by the 
spring directly G is released, For this purpose an india- 
rubber bellows I on a tube is fitted at J. It only re- 
mains to fit a strip across the I'ight-hand compartment 
with, perhaps, a wedge-shaped block (as in Fig. 3) to give 
extra pressure to the bellows. A couple of bent plates K, 
one a,t each side, are if or attaching to the camera front. 
The tube J projects for the pneumatic release at X. 
This should be fitted with a tap to keep the shutter open 
while focussing. The catch L and the pin M are used for 
the same purpose, or when long exposures are necessary 
and a cap must be used. 

Varnishing VioUn. — In preparing a violin for var- 
nishing, commence by sandpapering It ail over with 
No. 1 paper and freeing it from scratches. Go over 
the entire surface lightly with a clean, slightly damp 
sponge, and when the wood is dry it will be quite 
rough again ; rub with No. paper till smooth, and 
repeat the damping and papering vintil a dead smooth 
surface is obtained, quite free fron' scratches. It is 
not usual to stain violins, as a muon finer effect is 
got by incorporating the colour with the varnish. . 
The following process will give excellent results. 
Dilute i parts of good copal varnish with 1 part (by 
measure) of turpentine, and heat it quite hot, being 
careful not to let it catch fire. Go over the entire violin 
with this with a stiff brush, /tnd rub in as much as it 
will take at one coat i this will not be much it the wood 
was well finished. When it is quite filled, make a pad of 
cotton-wool, done up in a fine cotton or linen rag, 
moiuten this with turpentine, and clean the surfaces 
of the violin as rapidly as possible ; then put on a coat 
of spirit varnish, made thus : Colour i pt. of methylated 



spirit with turmeric and red sanders wood. In anotheir 
i pt. of methylated spirit dissolve 2 oz. of gum sandaraeh 
(juniper gum). Mix the two together, add .two table- 
spoonfuls of veniCB turpentine and 2oz. of white shellac, 
and when dissolved, filter through cotton-wool or flno 
muslin. This elastic spirit varnish gives the violin the 
warm amber colour so m uoh sought for. Lay on the varn ish 
carefully with a large, round, camel-hair brush, avoiding 
streaks, and not going twice over the same place. It 
will dry very quickly, and three or four coats may be 
put on daily till the desired colour is reached; rub 
' do'^vn with finely sifted pumice-powder and water and a 
woollen rS.g after every third coat. When a good body 
of varnish is on, the surface must be rubbed down with 
the I pumice-powder till it Is dull and. smooth all over; 
the pujnice is then thoroughly washed of. The final 
polish is obtained with tripoli and water, or crocus and 
linseed oil, on a rag, as before. After this is cleaned off, 
a brisk rub with the heel of the hand will give a surface 
like glass. The above instructions are applicable also 
to re-varnishing an old violin i but then it is necessary. 
In the preliminary sandpapering process, entirely to 
remove all traces of the old varnish. When that has 
been done, the work is identical with the above. 

Coloured Printing Inks. — Printing Ink is not 
usually made satisfactorily in, the absence of big 
plant, but below are given some simple instructions 
easily followed. Into a 5-gal. iron pot pour 6 qt. of 
old linseed oil, and heat gradually over a fire to boiling 
point. As soon as the vapours that arise from the 
surface will catch fire when a light is applied, rendove 
the pot from the fire and allow the oil to burn for 
a time; smother, the fiame by placing the lid over the 
pot. If the oil has thickened sufficiently, it will draw 
out into threads i in. long when dropped on a cold 
surface. If the oil is not thick enough, relight it, and 
allow it to burn down. If the oil is all right, stir 
till the frothing ceases, and put in gradually 6 lb. of 
crumbled amber resin, and keep stirring till all is 
melted. Then stir in IJ lb. of sliced curd-soap, ahd when 
the frothing has ceased, place it on the fire, and bring to 
boiling point, stiiTlng well all the time. Tills is printers' 
varnish. Varnish is best made out of doors; it smells 
unpleasant in boiling, and there is less risk of fire out 
of doors. To make brown ink, add varnish to a powdered 
mixture of 2oz. of burnt umber and loz. of rose pink, 
and grind till smooth with a muller. Indian red and 
Venetian red, toned with a very little lampblack, also 
give browns. A fine black ink may be made with 9 oz. of 
balsam of copaiba, 3 oz. of lampblack, 14 oz. of indigo or 
Prussian blue, or i oz. of ^ach, i oz. of Indian red, and 
8 oz. of dry turpentine soap. These are to be ground with 
the varnish till quite smooth with pestle and mortar or a 
muller and slab. For black varnish ink, 5 oz. of Prussian 
blue or indigo, or Hi oz. of each, tlb. of mineral lamp- 
black, andSt lb. of good lampblack, are mixed with warm 
varnish, and the whole is well ground on a slab with a ' 
muller. 

Primary and Principal Colours.— There are three 
primary colours — red, yellow, and blue ; the ten princi- 
pal colours are Chinese white or bai-yta white, yellow 
ochre, Naples yellow, vermilion, Indian red, madder car- 
mine, emerald green, ultramarine, Prussian blue, and 
ivory black or Indian ink, j 

Electro - brassing Solution. — For a solution tor 
electro - brassing small iron goods, dissolve 1 lb. of 
good yellow sheet brass in suificient warm dilute nitric 
acid to dissolve the brass without leaving any fi'ee 
acid; then add the whole to 8 gal. of rainwater. Now 
add liquor ammonia until the brass solution assumes 
a deep bitie tint, then add a solution of cyanide of 
potassium until all the blue tint disappears. Filter 
through calico and add an equal bulk of rainwater 
to form the brassing bath. This must be worked with 
an anode of good yellow sheet brass, which should dis- 
solve freely to maintain the solution in good working 
order. To obtain a uniform bright yellow deposit of 
brass on small iron goods held in basinets, some sKill will 
be required, as the character of the deposit is influenced 
by the temperature of the solution, the density of tbe 
current, the proportions of metals, the size of ttie 
anodes, and the movement of the articles being plated. 
Very thick deposits of brass might be dipped in acid to 
improve their colour ; it is not sale to dip thin ones. 

Glazing Torra-cotta Tiles.— A glaze tor terrarcotta 
tUes requiring only a moderate heat can be made from 
a solution of sugar of lead in hot water. Cover the tiles 
with the solution and expose to a clear red heat, A coke 
fire would probably be suitable, provided it does not 
touch the tiles in any way. A sagger, or receptacle, to 
hold the tiles may be made from a drain pipe. Limewash 
the Inside of the pipe and set the tiles with the glazed 
surfaces facing each other. Try Immersing them in salt 
or borax, and then bake or paint over with red-lead ; thU 
will give a deep red glaze. 



Cyclopaedia of Mechanics. 



19 



Repairing garble Clock Case.— To repair a broken 
corner of a marble clock case to Imitate grain, wbieh 
is light green, white, and black, a hard-setting cement 
can be iised which is made by mixing plaster-ot-Parls 
with white of egg. This can be used for re-forming 
the broken corners, and afterwards painted black and 
gently rubbed with furniture polish. 

Gum Bichromate Process of Photography. — The 

gum bichromate process of photography is an, old pro- 
cess, and is only suitable for large work, and for subjects 
that do not need much definition. The process itself is 
as follows. Gut some sheets of good cartridge paper into 
pieces rather larger than the negative to be printed from. 
Prepare "a 10 per cent, solution of potassium bichromate 
and in it immerse the cut paper for from two to three 
minutes, taking cai-e that the paper is cTenly wetted. 
The immersion may be done in ordinary daylight, as the 
paper does not become sensitive until it is iry. In a. 
room fi-ee from dust pin up the paper by the corners tO' 
dry. As soon as the paper is di-y it must be kept in 
the dark, or as carefully guarded from actinic light as 
silver paper would be. Make up a 40 per cent, solution 
of gum arable and filter and mix with it the pigment 
that is to be used, which would be either ordinary 'pow- 
der colours as obtained from the oilshop, or the water 
colours sold by artists; colourmen. The latter colours 
are preferable, as they are usually in a finer state of 
divisipn. A thin coating of the mixture is then evenly 
applied to the paper, smoothing out with a large badger 
brush; drythoroughly. The exposure may be timed by an 
actinometer, but is practically a trifle longer than would , 
be requu-ed to make a print in albumen from a negative 
of similar density. Lay the' print face downwards in 
cold water for htil an nour and note the result. If 
correctly exposed there will, probably be by this time a 
dim outline of the principal objects. Kaise the tempera- 
ture of the water and bathe very gently until the image 
Is well out. Soak for a few minutes in alum and rinse 
well to remove the bichi-omate ; this is all the fixing ' 
required. The paper should not be kept long after 
sensitising. Some examples of the gum process have 
been obtained by working up the softened gum with a 
brush. Carboti tissue allows of similar modifications. 

, Determining Contents ot Rectangular Tank.— To 
' determine how manygallons of water would be held by 
a tank of specified dimensions, first find the contents in 
cubic feet, and then multiply by 6~'23. JChe contents of 
a rectangular tank 6ft. by 9ft. by 4ft. Gin., eqvwUs 
6 X 9 X 4i = 243 cub. ft., so that the water contained 
should measure 243 x C'23 = 1,514 gal. (approximately). 

Making a Theatrical Bald Wig. — In making a 
bald wig such as isi worn on the theatrical stage, 
a piece of stout calico should be tightly stretched 
over a suitable dummy, whjch is generally a wooden 
block, and the calico should be tied or tacked round the 
neck of the dummy. Give the calico a coat of hot jelly 
size, which should be followed by two coats of flake white. 
The medium for applying the colour should consist of 
copal varnish, linseed oil, turps, and a few drops of gold 
size. Each coat must be dry and hard before the next is 
applied. The flesh tints may be obtained by mixing 
small quantities of, rose madder and Indian yellow witli 
flake white, the medium being the same as before. 

Simple Metronomes. — A metronome, a device fo) 
measuring and beating time in music, may be made 
with a piece of- tape and a weight, or it may be an 
elaborate clockwork arrangement. For the tape and 
weight metronome, the. distances from the centre ot the 
weiglit to the point ot suspension should be as follow :— 
No, ot Beats per Minute. ■ Distance in Inclien 

60 39-14 

70 2i■^o 

83 22-01 . 

84 U-87 

86 19-01 

> 90 17-39 

100 14-09 

105 12-88 

110 U-64 

120 9-78 

126 8-87 

130 8-34 I 

, Slightly more advanced than the weighted tape in sus- 
pension is the metronome illustrated by Figs. 1 and 2. 
It is, however, of simple construction though it will 
answer quite as well as a more elaborate arrangement. 
01 the compound pendulum, A is the rod, B the bob, and 
C a small supplementary weight which slides up and 
down the upper part of the rod. With c at the top end the 
pendulum, on beirife set in motion, will swing for twenty 
minutes or more at the rate ot about forty-eight beats 
to the minute ; when C is at the bottom end, near the 
pivots, the pendulum will swing f Or a shorter time at the 
rate of abotit 114 to the minute. These matters having 



been determined by experiment, the intermediate speeds 
are measured off on the rod; the divisions are closer 
together as they approach the top, as shown at Pig. 1. 
The pendulum should be cast in brass, and only the top 
part of the rod, on which the weight is to slide, need be 
tiled to vVin. in breadth and I'lin. in thickness. The 
pivots are shown at B (Figs. 1 and 2) j they are two pins of 
tempered steel filed to a sharp point and driven tightly 
into holes drilled through the projections on the sides 
ot the rod as sho-wn in Fig. 2. The points work on a 
smooth piece of brass E (Fig. 2) which is slightly hollowed 
out,on its top side in both directions for the purpose of 
enabling the pendulum to swing Itself perpendicular 
when set up on an uneven surface. A small steel spring 
is screwed on one side ot the weight C to keep the latter 
at any desired height, though it allows the weight to be 
slid easily up and down the rod when required. The bob 






:oii;£ 


!=■ 


f ,Q. 2- 1 1 


■ [ 

I 


A ' 

1 


Q 



A Simple Metronome. 

E is placed slightly off the' centre (to the left) to com- 
pv>nsate for the weight of the bend on the i-ight. The 
nuand has a mahogany base' G (Fig. 2) 3 in. by 2 in. by J in., 
A-rtth two uprightsPSJin. by Sin.by Jin, and a cross-bar, 
to support the brass plate E. 

Cutting Tiles.— A white glazed tile may be cut into two 
pieces bj' laying it flat on a soft wood board and cutting 
very carefully with a chisel. To reduce the size of a tile, or 
to take an irregular-shaped piece o'ut of it, break or pinch 
off pieces with a pair or pincers ot about 7-in. size. The 
edges can be rubbed down on a stone if required to 
be very neat. 

Cleaning Furs.- These are methods of cleaning furs, 
■(a) Eub with hot roasted bran, allowing the bran to enter 
the fur well. Then shake the fur and well brush, (b) 
Moisten bran with hot water and well rub it into the fur 
with a piece of clean flannel. Now take some dry bran 
and a clean dry flannel and rub this well in until the wet 
bran and the fur have become dry. To remove the bran, 
give the fur a good shake, a sharp but light beating with a > 
cane, and brush with a soft brush, (c) Mix and heat in 
an oven equal parts of flour and fine salt, and thoroughly 
rub the hot mixture into_ the roots of the fur. Now well 
shake the fur, then throw it over the back of a chair, fur 
side upwards, and brush out any of the mixture left, 
using the end of a soft brush, and giving sharp " dabs '' 
so as to get to the bottom of the channel formed by the 
parting of the fur, blowing well all the time. 



20 



Cyclopaedia of Mechanics. 



The Manufacture of Water Colours. — Oake and 

moist watei' colours are made by grinding the dry- 
pigments in a mill with gum water and a little 
§lyoerine or honey to prevent them teooming too 
rittle; the pasty material is rolled out and ovit into 
squares, partly dried, and then pressed in moulds or 
placed in tins. Por the moist colours more gum 
water Is ussd than lor the cakes. The gum water is 
made hy dissolving purest gum arable in twice its 
weight of water and straining through muslin, then 
adding a little glycerine and a few drops of oil of cloves. 
Very little glycerine must he used or the colours 
will tend to absorb moisture from the air and fade or 
become bad. 

Slaking Leather Case for CroQLuet Mallet.— The 
leatlier for a croquet mallet case need not be very stout, 
but it must not be fiimsy, unless it is backed with some- 
thing, or It will wring in the sewing, and the handle por- 
tion will be unsightly. The leather used for the straps of 
bags, etc., will be suitable. Before cutting the leather, 
cut from stout cartridge paper a pattern to the shape of 
the mallet. Fig. 1 is the cover for the handle, which is 3 ft. 
long and 5 in. wide j Pig. 2 shows the cover tor the mallet, 
which is 12iiu. long by 13 in. wide; while Fig. 3 is a 




Fig 4 

Making Leather Case for Croquet mallet. 

pattern for the two ends, which is 3i in. wide by 4i in. deep. 
Two small arcs are cut out of I'ig. 1, as A, B, so as to fit a 
hole li in. diameter cut in Pig. 2 after it is curved to the 
outline of Fig. 3. In Pig. 2, li In. is marked off at one side 
and the two corners are cut off, as and D. The circular 
hole is then cut out, the centre being aboiit 4i in. from 
the left-hand side, so as to be in the centre of the case 
when finished. In Pig. 3, lin. is allowed on top for a 
lap. The pieces E and r (Pigs. 2 and 3) will form them- 
selves into flaps if a piece is grooved out along the dotted 
line. To get the piece. Pig. 3, a good shape> cut an 
oblong piece to the measurements given above and fold 
it down the centre, and then cut off the corners G and H. 
I'ig. 1 is now sewn imto cylindrical form so as to take 
the handle, the cii'cular piece, H in. diameter, as cut out of 
Pig. 2, being sewn to one end, the other end, with curves 
^ and B (Pig. 1) , being fitted into the socket hole at J 
(Fig. i), and the straps and buckles sewn on at K and L. 
To give a good appearance to the case when finished, 
a little plush may be fixed in with glue paste i if de- 
sired, a cheaper lining can be used. 

Notes on Re-paint)ng a House. — In commencing 
to re-paint a house, begin in the upper rooms, first 
washing off the ceilings, then stripping off the paper 
from the walls by applying water just where it is 
wanted, allowing sufficient time for it to soak, and re- 
moving a piece at a time. It a little soda or lime has 
been put in the water so as to more easily remove 
the paper, wash the work with dilute caustic soda. 
Contagious matter and certain insects are frequently 



retained In the paper, and the caustic soda acts aa 
a disinfectant. Eepair the bad places with plaster 
and whiting ; and it is sometimes desirable to coat with 
size to stop suction, and to put on lining-paper to make a 
sound job and hold the plaster together. The next job 
is to clearcole the ceiling. Put some whiting in a pail, 
cover with water till the lime in the whiting is slaked, 
pour off the water, and thoroughly mix in some hot size 
and add colour at the same time, it the ceiling Is to be 
coloured, or a little black if the ceiling is to be ctuite white. 
The black removes the yellow tone or raw appearance of 
the white. Strain the colour through canvas beloi'o using. 
The first coat for the ceUing is used thin and hot; the 
second is used with the chilled coloiir, so that it will go 
on thick. Do not lay the colour off, as in oil-painting, but 
put it on with short strokes, in varying directions, so that 
the light from the windows will not catch the lines likely 
to be made by strokes of the brush. The distemper has 
to be put on filll, as contrasted with oil-colour, which 
has to be spread, when the ceiling and walls have been re- 
paired, and the ceiling coloured, the paintwork is washed 
and rubbed with pumice-stone and soda-water, bad places 
being afterwards filled up with putty. Sometimes panels 
have to be filled up with distemper, and rubbed down 
with a flat cork covered with glasspaper. This latter is 
hard work it there was too much size in the distemper. 
When the flUing-up has been brought to a surface, it 
should have a coat of paint, which should be nearly all 
oil. Door frames, window frames and sashes, and all , 
wood mouldings, should have their corners scraped and 
brushed out. The mantelpieces should be well washed 
with strong soda- and lime-water, which should be kept 
on for atlme so that it may penetrate. The mantelpieces 
can then be washed off with clean water and allowed to 
dry. Having got the woodwork to a fairly level lace, coat 
it with colour. Colour the door frames first, and then the 
edges and panels of the door. After laying off the 
latter, commence the rest of the door at the middle 
upright stiles, afterwards doing the cross stiles. Finish 
by squaring off the two outside stiles, always remember- 
ing that the object is so to put on colour that an even 
smooth surface is obtained quickly. Be careful of the 
glasspaper, and bear in mind that its purpose is to make 
smooth, not to take off paint. Also remember that a 
brush mark in the first coat wUl show in the last one. 
Commence priming and painting at the right-hand 
corner of the house, doors, rooms, and windows, working 
to the left all through the house. If convenient, leave 
the staircase to the last, previous to preparing the skirt- 
ing, for which sienna is the best pigment, as it does not 
show the damage as much as other colours. The stair- 
case stringing may be painted plain, coloured, or it may 
be grained and varnished. It the outside doors are much 
cracked or blistered, the old paint must be removed. 
This may be done by brushing on a solution of 2 lb. of 
washing soda in 3 gal. of water, thickened with Ume dis- 
solved in hot water. When softened, the paint is scraped 
off, or, instead, the paint may be burnt off with a flame. 
The flame is the better method, as the soda-water may 
leave moisture, which is the cause of bUsters. In painting 
street doors, precautions should be taken against sub- 
sequent blistering. On this account, it is wiser not to 
use water or any stripping material whatever on the 
door, but to burn off the paint with flame. Keep the 
brushes in oil overnight— not in water. Of course oil, as 
far as possible, should be kept out of the colour, as that, 
as well as water, wUl cause blistering under the action of 
the sun. In preparing the front of a house for repainting, 
begin at the rignt-hand side, and clean out the spouting, 
windows, etc. ; continue in the same way to the bottom, 
rubbing downwards. Commence painting at the spouting, 
window sashes, and panes. Then work down the front 
with a coat of priming, taking doors and shutters in due ' 
course. For a black and dirty compo. front, it is best to 
stain the lead with black to a light grey, as the next coat 
will give it a solid appearance. In mixing colour for out- 
door work, use principally or wholly boiled oU, unless it 
be for decorative parts of the house, when the ordinary 
method may be employed. The compo. front may be 
repaired in places it necessary with Parian cement, as 
this can be smoothed off and painted immediately. 

Preparation of Selenium.— Selenium is a non-metal- 
lic element with properties somewhat like sulphur. 
Selenium in combination with oxygen forms several 
acids, but cannot be said to form salts like thosB of 
metals j it does, however, unite with chloriue in several 
proportions. The best known chlorides are selenium 
monochloride and selenium tetrachloride. These pro- 
ducts are obtained by the action of chlorine gas upon 
selenium. 

Removing Wool fVom Sbeepskin.— Soak sheepskins 
in lime water until the wool can be removed by scraping 
with a two-handled blunt knife: or leave tlie skin in a 
dark, warm, and moist place until sulBeient decomposi- 
tion has taken place to enable the wool to be easily 
scraped off. 



Cyclopaedia of Mechanics. 



21 



Mounting Photographic Prints.— This is the plan 
adopted by professional photographers for mounting 
prints. Immerse the trimmed prints in water for a few 
minutes and then place face downwards otie on the other 
on a sheet of glass. Squeeze out the excess of water with 
a roller squeegee and blot off the surface. Brush o-ver 
the back of the print with cold starch paste, free from 
lumps, takins care that the edges of the print are well 
covered. Raise the print by the corners, lay it in 
position on the mount, place over it a sheet of iluffless 
blotting paper, and roll into contact. Continued or 
heavy rolling is unnecessary. It too much starch is used 
it will be squeezed put around the edges of the print i it 
too little is used-the print may not stick at all. Should 
any starch spread on to the mount it is sometimes 
advisable to remove it by sponging over the whole 
mount. In mountitig, first estimate the position of two 
opposite corners, then lay the print down so that it 
touches the mount diagonally. Starch paste more than 
one day old should not be used, and aU lumps, even very 
small ones, should be carefully removed. Platinotypes 
require more starching, and do not stick it the undried 
mounted prints are laid together. 

Making Three-legged Folding Fishing Stool.— 

Below are instructions <Jn making an angler's three-legged 
folding si ool. Commence by marking out the section filll 
size as shown by Fig. 1. Make a three-legged bolt out 
of fs-in. iron, as shown at A (Fig. 1). Thread the ends, 
and fit them with circular brass nuts B ^in. thick, 
and square washers C and D. Each washer musi; be 
drilled in the centre and the four corners. A hole must 
be drilled to take a No. i screw. Three pieces of hickory. 



under the footings of the wall and make It form part of 
the same mass us the engine foundation, so that the 
weight of the building helps to steady the foundation. 
A stone bedplate should be provided between the con- 
crete and the engine bed. For securing the engine to the 
foundation, holding-down bolts with anchor plates at the 
bottom ends may be buried in the concrete, being first 
placed in their exact positions with the aid of a template 
marked off the bed of the engine. The upper ends of these 
holts are screwed to receive the nuts which hold down the 
engine. Another method is to cast holes in the concrete 
through wihich the bolts may be passed downwards, in 
which case the heads of the bolts may be at the top and 
the nuts are tightened up through hand-holes constructed 
at the bottom ends, but this necessitates leaving a trench 
for access to the hand-holes. Cotters at the bottom 
ends of the bolts are easier to adjust than nuts. 

Inserting New Wrest plank In Piano.— Wrest- 
planks of pianos should be built up of three sections— a 
beech centre, a maple or sycamore facing Jin. or jr in. 
thick, and a pine backing. If the facing aione is split, it 
is onijr necessary to replace that portion ; but if the 
plank is so split that a new fane must be inserted, pro- 
ceed as follows. First remove all the wires. If the 
covered ones can be usedagain, thread them on a piece 
of wire in the order in which they were taken off. Kemove 
the wrest-pins, and with a stout piece of brown paper 
and heelball make a cl^an imprint of the holes, bridge, 
etc. Carefully remove the bridge screws or bolts; 




Fig I 

Making Three-legged Folding Fishing Stool. 



ash, or lancewood about 18 in. long, and properly shaped, 
can be used fox- the legs. Bore the centre of each leg 
with a i>5-in. bit, and fit the washers on. Put the legs 
on the centre bolt and screw up, leaving sufficient clear- 
ance for the stool to open properly. The ends of the 
bolts should then be cut off, .but enough should be left 
beyoiflfc the nuts for riveting. Open the stool to the 
required (width and cutoff the ends top and bottom to 
the correct bevel, then take to pieces and finish with 
sandpaper and French polish. , Three pieces of strong 
webbing are sewn together at the corners (as shown at 
Fig. 2) to form a triangle the size of the stool when open. 
Put the stool together, rivet over the ends of the bolts, 
open as at Pig. 3, and tack the webbing on the corners at 
the top. 




How to Make Dry Soap.— A good dry soap can be 
made without the aid of expensive plant. To 40 gal. of 
water contained in a steam-jacketed pan add from 2 to 
2i cwt. of soap cut up as fine as possible. A white curd 
soap with free lathering properties is best ; on no 
account must a yellow soap be employed. Tbis mixture 
is stirred until the soap has entirely dissolved and the 
mixture is pasty. Now add, in small quantities at a 
time, i cwt. of soda ash, stirring well all the time, then 
run the sOap into shallow galvanised iron trays to cool. 
When cold, the mass will begin to break up into' small 
pieces. It should be ground to powder in a mill— prefer- 
ably an edge runner mill or disintegrator. i 

Foundations for Gas Engine.— A solid mass of Fort- 
land cement concrete makes a good foundation for a gas 
engine, and is easily constructed. Solid brickwork IS 
also used, but the excavation required is more than with 
concrete on account of working room being required for 
the bricksetters. The best shape for the foundation is 
as nearly cubical as possible ; it made long and narrow, 
and deeper than it is wide, there is a tendency to, rock. 
To prevent vibration being conveyed to the waUs of the 
buuding-such foundations are sometimes isolated by 
forming an open trench all round ; but it, the site of the 
engine is near a wall it is better to lay a concrete floor 



the old plank may then be chopped out with a mallet 
and stout chisel. The prepai-ed plank should be cut 
to exact length and secured in position with good 
hot glue, and screwed up tightly tor several days 
with iron cramps having deep jaws. When these are 
removed, clean up the face for the bridge and holes 
tor wrest-pins, their exact positions being deter- 
mined by means of the brown paper, which is laid in 
position, and secured, while a sharp tap is given with a 
hammer and centre punch where the holes should be 
bored. The bridge should be fastened with hot thin 
glue and brass pins and the necessary bolts, screws, or 
dowels, and a piece of mahogany or birch capping laid 
on. But if the instrument is fitted with a half lid it 
should have a final cleaning up, and several coats of 
white hard spirit varnish should be applied before the 
wrest-pins are Inserted. 

Making Golf Balls.— GoK balls are made from pure 
guttapercha, procurable In rods and ready for cutting 
into pieces suitable tor the mould, which should be 
of size 27i. To prevent waste, the cutting is done with 
a knife operated on the guillotine system ; the pieces 
should be slightly larger than will exactly fill the mould , 
the superfiuous guttapercha being afterwards pared off 
with a very sharp knife. Before moulding, the gutta- 
percha requii-es to be thoroughly softened in water 
kept hot over a fire. The guttapercha is then placed in 
the engraved mould, and subjected to great pressure. 
After the balls are made they should be put away in a 
dry, warm place for about three months to allow them 
to become thoroughly seasoned. They are then given 
three coverings of special paint, a small qua,ntity being 
put on the palm of one hand, and the ball rolled between 
the palms ot both hands. Two days should elapse 
between each covering, and in a week after the last 
covering the balls are ready for use. 



22 



Cyclopaedia of Mechanics. 



Preparing Tartaric Acid,— Tartaric acid is largely- 
made from wine lees, i.e. the deposit formed when 
wine is kept in casks. Tamarinds may be extracted 
with boiling water, the liquid being mixed with a little 
pipeclay and filtered through animal charcoal to de- 
colourise it. Powdered chalk should be added to the 
liquid until it ceases to effervesce j the precipitate should 
be collected on a filter cloth, and a solution of calcium 
chloride ad-ded to the filtrate until it ceases to give a pre- 
cipitate ; the precipitate is tartrate of lime, and should 
l)e collected along with the first precipitate. The pre- 
cipitate should be mixed with a Uttle water and dilute 
sulphuric acid added in vei-y slight excess. The liquid 
should then be filtered, evaporated gently to a syrup, 
and left to crystallise. The crystals may be washed two 
or three times with cold water, which may be added to 
the next lot of acid required, and the crystals of tartaric 
acid should be dissolved in the least possible quantity 
of hot water, and the solution evaporated and allowed 
to crystallise again to get rid of the sulphm-ic acid. 

Stereoscopic Photography.— Stereoscopic effect or 
the appearance of relief depends upon the combin- 
ing in one in the stereoscope of two representations 
of the same scene taJ^en from slightly different points 
of view. Stereoscopic photographs, therefore, are 
best obtained with a camera having a pair of lenses 
fitted side by side. These lenses should be accurately 
matched as regards focus, ratio, aperture, colour, 
etc., and should be 2i Ih. apart, which is about the 
distance between the eyes. With this camera two 
pictures will be taken at the same time. Paired lenses 
are sold for the purpose. A method of taking stereo- 
scopic photographs with one lens only (a half-plate 
camera being used) is to employ a couple of mirrors set 
at such an angle as to have two points of sight. These 
mirrors are placed in front of the lens and reflect the 



ordinary device of using wire gauze, on account ^f the low 
igniting point of mixtures of acetylene and air ; while if 
high pressures are used so that the rate of flow shall be 
greater than the propagation downwards, more air is 
sucked in by the uprush of the gas and the velocity of the 
explosion is again increased. The best results in acetylene 
Bunsens have been obtained by takingaBunsen burner m 
which a constric fcion in the air-tube creates a high velocity 
at the particular point where the explosive wave starts to 
propagate downwards. 

Cleaning White Kid Gloves and Shoes. — For 

cleaning white kid gloves, make a paste by boiling 
1 part of white curd soap with i parts of water, and 
adding a small quantity of ammonia ; place the glove on 
a wooden hand and rub well with the paste, laid on 
with a sponge, until the glove is thoroughly cleaned. 
Any worn parts maybe improved by rubbing in a little 
magnesia or white French chalk. Rub the glove dry 
with a clean cloth, and, after removal from the hand, 
work the glove about to render it supple again, then 
press with a heavy weight. Kid boots can be cleaned 
with the same paste, followed by the French chalk. 

Removing Grease Stains from Wall -paper. — 

To remove grease stains from wall-paper, make a thin 
paste by mixing powdered starch or flour with ben- 
zoline (petroleum spirit). In this mixture dip a sponge, 
and with it make a ring around the stain. While the 
ring is still wet, thoroughly soak the stained 
parts with the mixture. Allow the paste to dry,' then 
remove the powder with a clean soft brush. The object 
of making the ring around the stain is to prevent the oil 
being carried away from the spots and forming a ring in 
the paper, as it does by the usual method of treatment. 

Making Brass Dog Collar.— These are instructions 
on making a brass collar for a dog. Cut a strip of 




o 
o 



FiO. I 



000 



Sliding Front of Camera for 
Stereoscopic Photography. 



Fig. 3 



image through the lens on to the plate. The instrument 
is known as a stereoscopic transmitter. Still objects, 
and ordinary landscapes in which there are no moving 
figures, can be taken with only one lens if the 
camera is fitted with a sliding front. Such a camera 
must have square bellows. The above sketch explains 
the construction of a sliding front. The first ex- 
posure is made, and A is then pushed along> until 
the mark B points to t^e mark C. The opening in 
the front board of the camera is shown by dotted 
lines. The distance between the two points may be 
varied according to the distance of the principal 
object. The farther the principal object is from the 
camera the greater must be the separation between the 
two points. Sometimes it is possible to obtain stereo- 
scopic photographs by moving the object, as, for example, 
a vase of flowers. In this case the camera and lens are 
stationary and an ordinary quarter-plate camera can be 
used. Such a camera may also be used if it is fitted with 
a board as wide as the base from back to front and about 
double the length of the original base. Two parallel 
slots are made in this extra baseboard, and thumbscrews 
pass through these into the original baseboard. The 
camera may thus be slid easily from one position to the 
other and clamped. A great deal depends upon correct 
mounting of the prints ; this is a process that is described 
on another page, but suffice it to say that the picture 
that was on the left hand of the camera becomes the 
right-hand print when mounted. 

Bunsen Burner for Acetylene Gas, — To make a 
Bunsen burner for acetylene the tube must be ex- 
tremely narrow, and it is even then found to be very 
liable to flash back, while it requires a high pressure 
to bring about satisfactory combustion of the gas with 
an absolutely non-luminous flame. One of the chief 
difficulties to be overcome is due to the range over 
wliich mixtures of air and acetylene are explosive, and 
which lies between the limits of 3per cent, and 82 per cent, 
of acetylene. The propagation ofthe explosive wave down 
the burner tube cannot be satisfactorily stopped by the 



Pro. 2 
Making Brass Cog Cellar. 



.ff?i_ 



-jQ 



Pig. 4 



brass IJin. wide, and equal in length to the circum- 
ference of the dog's necK, with an additional allowance 
for lap at the end, as shown at AB (Fig. 1). Punch 
two small holes at the opposite end, into'*^ which 
the ends of the wire staple (Fig. 2) will fit, and also 
punch out the slots at the end AB. Now told over the 
long edges along the dotted line shown, until the section 
formed is as shown by Fig. 3. Then wire, along each 
side in a crease iron j this would make the section as 
shown by Fig. 4. 'lurn the collar round and solder the 
staple firmly in position and flush on the inside. Any one 
of the slots on the end opposite the staple end would 
then hook over the staple, and the collar could be 
fastened with a small padlock. 

Use of Watch Depth Tool,— A depth tool is used 
more in making than in repairing watches. It is 
required lor scoring off the exact position of the 
pivot holes upon the watch plates, previous to drilling 
them. It consists of two parallel frames, hinged 
together and capable of being adjusted by a thumb- 
screw to any required distance apart. Each frame 
is provided with runners like a small pair of turns. 
In one frame a wheel is placed, in the other a pinion. 
The frames are then adjusted to such a distance apart 
that the wheel runs nicely with the pinion. The outside 
points of the runners can then be used as a pair of com- 
passes to transfer the exact distance to the watch plate. 

Removing Varnish from Boots.— It is difBoult to 
remove the varnish by means of a solvent from patent 
leather boots ; it is better to tree these up tight and rub 
down with No. 14 sandpaper, then with No. 1. and finally 
with flour sandpaper, and when the surface is smooth, to 
revarnish. The above process will also be suitable if 
the boots are of calf. But if it is desired afterwards to 
clean the boots with blacking, first soften the old varnish 
with a little spirits of wine on a piece of good cloth, 
and then apply a coat of dubbin. 



Cyclopaedia of Mechanics. 



23 



Browning Bottoms of Boots..— To brown the bottoms 
of boots, put some thin bx'own paste on the bottoms and 
well sleek them just before they are auite dry ; lepeat till 
an even colour is obtained, and finish with white heel- 
ball and cloth. Or whiten theleather, and burnish with a 
warm burnisher ; this will give a darker brown. Finjsh 
as above. Another method is to rub a little of the colour 
on a damp sponge, apply to the boot bottoms, and finish' 
as above. Anjr brown colour will give the desired eHfect. 
To gain an easier finish, instead of using white heel-ball, 
make' some white or brown fake, and, after burnishing, 
place a little on the boots with the finger, and when 
nearly dry, rub off with a cloth. 

Bleaching Straw.— Brown straw may be bleached 
by boiling in a solution of washing soda, and, whilst 
still moist, subuiltting it to the action of sulphurous 
acid. To do this, the straw must be hung in a nearly 
closed chamber ; a box or barrel will do if only a small 
quantity of straw is to be bleached. , A pleca of roll 
sulphur is placed on a saucer and set fire to by a hot 
iron rod; the saucer is then placed in the chamber 
(below the straw, but not too near it) and left burning 
for some time. After bleaching, the straw should be 
washed with warm water to remove excess of sulphurous 
acid. 

Photographing Several Objects at Different Times 

on One Plate.— It is possible to take twelve different pic- 
tures of various sub,iects on one 5-in. by 4-in. plate, one 
lens only being used. A repeating back to the camera 



the burner, otherwise the Bunsen flame will be one-sided 
and cause the mantle to shrink more on one side than 
the other; the result being that the mantle will be out 
of shape after burning a few hours. See that all burners 
are fitted perfectly upright and that the right-sized rod 
is used wfth every burner. The rods should be fitted 
into the burner pretty tightly ; it they fit loosely they 
may be packed with a little asbestos. Also note that the 
Bunsen flame of the Kern burner is quite different from 
the ordinary "0" burner. The ring just above the 
■wheel should be of a whitish-blue colour, not green. The 
mantle ought to be fully incandescent from top to 
bottom, and no flame should be visible outside or above 
the mantle. Should the Bunsen flame of the new burner 
resemble that of the " " burner it would indicalje 
that the nipple on the burner is too large, or that the 
flame when lighted on the nipple (without the Bunsen 
tube) is not vertical. This should be remedied, as it 
means a loss of forty per cent, of light. 

Skeletonising Animals' Skulls The usual method of 

cleaning animals' skulls is to soak the bones in water 
frequently changed until the flesh becomes decomposed 
and able to be removed with the fingers and small pieces 
of wood. This takes some time and is disgusting work. 
As an experiment, try some yood ashes in the water. 
Begin by using, say, a handful of wood ashes to a gallon 
of water, and increase gradually. 

Connecting House Drain to Deep Sewer,— In laying 
al-in. diameter house drain, which is 50 ft. long, to join 



o r 


Al 


^s 


= 1 


Ao 


i 




B 


o 


" 


JJ 




O 





U 1 






c 








D 1 




"-3 


B 




o A 









o 



Double Repeating Back for 
Camera. 

is needed for such work.- But where mbre than one 
row of pictures is taken, the back must have a vertical 
sliding movement as well as a horizontal one. The 
reversing back is made in two frames : the first or back 
frame fastens to the camera back frame or into the 
reversing back catches ; the second consists of two rails 
A A, between which runs a sliding board B with opening 
C of the desired size, say 1 in. square. Across from A to A 
run the slide rails D, with a catch in the top and three 
cuts in the slide to engage with the catch. For the first 
exposure the slide is put in as shown in the sketch, and 
is moved forward for each successive one. After three 
exposures have been made, the sliding board is then 
lowered to the next point and the slide pulled back to 
the first position again. By lowering the board and 
pulling back the slide twice more in this way, twelve 
exposures, each about lin. square, may be made on a 
5-in. by 4-in. plate, as has been stated. 

Particulars of Welsbach Burner. — Mention is 
made below of the principal points to be attended to in 
order to get good results with the Welsbach burner. 
The burners ordinarily supplied are intended for use 
with gas of from fifteen to twenty candle-power, and 
it is an advantage to know whether the gas comes 
within this range, since it is generally necessary to 
use slightly larger nipples for a poorer gas and smaller 
nipples for a richer gas. It is also necessary to know the 
average pressure during lighting hours, and to select the 
nipple most suitable for that particular pressure ; if, for 
instance, the pressure varies from 1 in. to 2J in. during 
lighting hours, select a nippl^ most suitable for IJ-in. 
pressure. Having decided on the most suitable nipple, 
take care, that it is screwed into the socket gas-tight, as 
the least leakage will cause a bad Bunsen fiame ; the 
nipple itself should be examined to see that its interior is 
quite free from dust, grit, or other foreign substance, 
and on lighting the gas on the nipple (without the 
Bunsen tube) the flame ought to be perfectly; vertical. 
See that the wheel on the top of the Bunsen is exactly 
centred, and lies evenly, perfectly flush with the top of 




Connecting House Drain to Deep 
Sewer. 



ȣ; 



a sewer which is 20 ft. below the level of the house, the 
pipes should be laid at a reasonable depth, say, 2 ft. 6 in. 
or 3 ft., with a proper fall to the intercepting chamber. 
The drain should then either be taken down by a 
quick fall (as in Fig. 1) , oi- by a vertical drop (as in Fig. 
2). In the figures, S Indicates the sewer, and C the inter- 
cepting chamber. Such a case as this is neither con- 
templated nor provided for in the Model Bye-laws. 

Watch Going too Fast.— A watch will sometimes 
gain even when the regulator is pushed as far as possible 
towards " slow." The regulator of every watch is pro- 
vided with two curb pins, between which the outer coil 
of the hairspring passes, and in the case mentioned it 
may be found that the hairspring does not vibrate freely 
between the curb pins, but binds against one of them. 
If it already vibrates, opening the curb pins to give 
more play will cause, the watch to go slower. 

Varnishing Violin.- Both oil and spirit varnishes are 
used on violins i the former give quicker results. Oil 
varnishes should be allowed an interval of at least 
two days between each coat; each kind of varnish 
should be dulled with pumice before applying another 
coat. Coating with boiled oil before varnishing is not 
advised. A yellow tinge may be imparted by the aid of 
gamboge and turpentine. A quantity of essential oil of 
turpentine being put in a cup, it should be placed in a 
water bath on a gas or oil stove and brought to a gentle 
heat and as much gamboge added as the oil will take up. 
Carefully strain, and apply witfi a camel-hair brush ; a 
second coat may be given in three hoars' time. The 
first coat of good spirit varnish may be applied the 
next day. 



Cyclopaedia of Mechanics. 



Making Polishing Buffs.— Buffs tor polishing metal 
are made by fastening thick buff leather with best 
strong glue to the edges of wooden wheels, the ends of 
the leather being secured by nails until firm. The edges 
are then covered with glue and rolled in the emery 
powder (which should be placed in a flat tray), making 
sure that a good coating is on the leather. This 
process must be repeated as found necessary. 

Curing Sheepskins.— Below is given information on 
curing and dyeing sheepskins. The skins should first he 
" fleshed," tliat is, freed by a sharp knife from any fat or 
flesh. They are then cured or tawed by placing in some 
preservative •. a suitable one consists of 1 lb. of alum, 
1 lb. of salt, about i peck of bran, and 1 gal. of boiling 
water. This should be well mixed and covered for some 
time to allow the bran to swell. The skins are left in the 
preservative for a day or two, or until the tawing is com- 
pleted, which may be known by a white line being left 
when a part of the skin is folded and pinched. The skins 
are now taken out, stretched on a frame or door, and 
curried. This is done by scraping in every direction to 
remove the inner part of the skin. Or they may he 
curried and stretched after. They are nowdried and the 
scraping continued, being supplemented by shading and 
rubbing between the finger knuckles. 

Setting Out Dovetailing.— In setting out dovetailing 
first set out the shoulder lines on each piece ; if the ends 
are shot true this may be done by a gauge. Mark off 
the centre of each socket, and then half the breadth of 



to a fine paste with water, and coat the suriaoe to 
be bronzed thinly and equally. Build up a clear coke 
fire on the forge, over which move the article about 
until the paste is quite dry. Place some coal on the 
fire to render it smoky, and expose the article to the 
fumes till the sui-face is quite black. Blow up the 
flre until it again burns clear and is free from smoke, 
then move the article about over the fire and as close as 
possible to -the red-hot coke until all the soot is burned 
off. Allow the article to cool, and brush oit all particles 
of crocus, soot, etc. Tie on the head of the smoothing 
tool a covering of parchment, or one or two thicknesses 
of lasting, and with the bright hammer go over the 
bronze surface until it is smooth. An acid process for 
finished work is as follows :— Dissolve in vinegar two 
parts of verdigris and one part of sal-ammoniac. Boil 
this solution and skim the surface clear. Add water to 
the solution until no white precipitate remains at the 
bottom of the vessel. Now thoroughly clean the article 
to be bronzed, and immerse it in the boiling solution 
until the desired shade is acquired ; then rinse in water 
and dry with sawdust. If the solution is too strong, the 
bronze will not adhere very firmly, and a little friction 
will remove it ; if the article is not well dried a green 
coating occurs on exposure to air. Both the above 
methods require practice before the desired colour and 
permanency can be obtained. 

Permanence of Photographic Prints.— If the direc- 
tions given by the makers of the paper are followed, 
pure chemicals used, and separate toning and fixing 




^'XT.; 



FlO 3 



the sockets on each side as at A (Fig. 1). Make a tem- 
plate as shown at Pig. 2, the edge AB being square to 
AC; AD and CE should be about 80" to the edge AC. 
Then mark out the sockets with a template and a sharp 
pencil (or awl) as indicated at Pig. 2. Saw carefully 
in the waste parts; then place the socket piece on the 
pin piece, and mark the shape of the latter by using the 
end of a saw placed in the sockets (see Pig. 3). A, Pig. 1, 
F, Fig. 2, and A, Fig. 3, refer to the same side. 

Cleaning Coral.— Coral that has become very dusty 
may be cleaned in this manner. In a large pan full of 
soapsuds hang the coral in a net so that it is submerged, 
but does not touchelther the sides or bottom of the pan, 
and place the pan on the fire and boil. Then take it off, 
throw away the water, wash the coral in clean water, 
replace it in the net, and put it back in the pan as be- 
fore ; fill up with clean water and again bring to the boll. 
Remove coral, rinse In clean water, and .allow to drain. 

Dressing Tarpaulins,— Eailway companies generally 
vise a prepared sheet dressing tor yellow tarpaulins. For 
a yellow dressing, use boiled linseed oil coloured with 
yellow ochre ; if it does not dry quick enough, add a little 
patent driers. First give the canvas a good dressing 
with plain boiled oil ; when that is dry, coat both sides 
with the coloured dressing. The dressing should take 
several days to dry j it it dries quickly it will be liable 
to crack. 

Bronzing Metal Urns and Other Vessels.— Metal 
tea-urns, spirit measures, etc., are usually bronzed after 
all seams have beeff brazed and .the metal has been 
worked to shape. One method of bronzing is as 
follows. First pickle the article in spirit of salts, 
then scour it quite clean and tree from grease with 
sand. Procure some crocus of the dfblred shade, ml:£ 



baths, there is little danger of P.O.P. prints fading. 
It is perhaps in the fixing and washing of the prints that 
errors are likely to be made. The fixing bath, which 
must not be in an acid condition, should be atthe normal 
temperature and suflloiently strong ; it either of these 
points is neglected fading of prints may result. The bath 
should be made with warm water, as there is consider- 
able loss of heat in dissolving hypo, and when the 
temperature is low the bath does its work too slowly. 
■When the prints are put in the hypo the unaltered 
silver is changed into silver thiosulphate, which is 
insoluble, and then into a double thiosulphate of silver 
and sodium, which is soluble. Unless the bath is strong 
enough to form the double thiosulphate, stains and 
fading may result. The proper strength for P.O.P. is 
. hypo 3oz., water 20 oz. For albumen prints use a lO-per- 
cent. solution of hypo. The prints must be kept moving 
while they are in the fixing bath. It Is important that 
after fixing is completed every trace of hypo should be 
removed from the print. For this phrpose a mechanical 
washer may be used; this keeps the prints moving 
round the washer whilst the hypo sinks to the bottom 
and is syphoned off. Or the prints may be transferred 
by hand backwards and forwards between two dishes 
alternately filled with clean water. Atter about forty 
minutes' thorough washing the prints should he free 
from hypo. A test, however, should bo applied. Put a 
small quantity of starch into a test-tube and add a few 
drops of a solution of iodine, thus forming blue iodide 
of starch. Pour half of this blue iodide into another 
test-tube, and, lifting one of the prints from the wash- 
ing water, hold it by one corner ahd allow the last few 
drops of the drainings from it to tall into one of the 
test-tubes. If any hypo is present in the drainings it 
will turn the blue solution wliite. Compare the colour 
of the solutions in the tubes by holding them side by 
side against a sheet of white paper. 



Cyclopaeclia of Mechanics. 



25 



Making Bar Soap.— Ag a preliminary trial in soap 
making, try the cold process. Cocoanut oU should , 
be used to the extent of from 23 to 50 per cent, it 
possible, as it not only rapidly saponifies but ap- 
pears aiso to hasten the saponifloation of other oils 
mixed with it, and forms an easy lathering soap. 
For trial, dissolve in li pt. of water i lb. of caustic 
soda (that in hermetically sealed tins for preference) ; 
place the lye in a jug:. Now raise the temperature of the 
oUs to 110" F., pour into a large bowl, and add the lye 
very slowly, stirring well with a stick. When the lye has 
been thoroughly mixed with the oils the mixture may be 
poured into a mould. An efttcient temporary mould may 
be made by lining the inside of an old box with a piece of 
old cotton cloth, wetted, and folded in several thicknesses. 
Pour the mixture into the cloth, cover the box over, and 
place it in a warm place for from twelve to twenty-four 
hours. If the mixing has been properly performed, a 
block of hard soap will be prodxiced, which may be out 
into bars with a wire. 

Boof Gutting Into Side of Dome.— It is required to 
obtain the proper sweep for the plate that runs up the 
slope o( a roof which cuts into the side of a dome. 
It the dome is a semi-sphere, then the section of the 
dome formed by the plane of th^ roof passing through 



a minute, and when this speed is obtained let go the 
shutter. BTow make a time exposure on the same image, 
but on another plate with the wheel at rest. The first plate 
on development will show a blurred arc where the image 
of the bright tinfoil moved across the plate. The propor- 
tion the movement bears to the complete arc is the speed 
of the shutter expressed-in fractions of a second. To find 
the degree of movement, measure on the negative show- 
ing the wheel at rest the width from side to side of the 
tinfoil, and subtract this from the extension of the arc. 
Now ascertain with the compass howmany times the 
remainder is contained in the oircumterence ot the 
wheel image and the answer is the traction ot a second 
exposure that the shutter gives. 

Mixing Oil-colour Paint.— For painting any surface 
that has to stand the stress of weatlier the paint should 
be of as good quality as possible. For a good oil paint take, 
for each pound of colour required, ilb. genuine white- 
lead, 1 oz. of patent (paste) driers, or a small quantit j- of 
terebine, and mix it to the required consistency with a 
mixture of raw linseed oil 2 parts, turpentine 1 part. If it 
is required to dry with a good gloss, replace half the raw 




Boof Cutting into Side of Dome. 



It would be a part of a circle. Produce A B, the plane of 
the roof (Pig. 1) , until it joins the plan at A' j bisect A' B 
to give the centre O', and then draw a line at right angles 
to the ground line from A to cut the plan at C. The dis- 
tance AC would be half the width of the section's base. 
To draw the section, set ofl^ a line at right angles to, and 
on both sides of, AB (Pig. 3). Make AC on both sides 
of AB equal to AC (Pig. 2), also make AB (Pig. 8) equal to 
ABCPig. 1). Then mark oil from A, AG' on the section, 
equal to AO' (Pig.l). liseO' as centre, and with radius to 
B draw the arc shown, Pig. 3, and this would be the part 
to be cut from the plate, so that ib would fit the dome. 

Making Stannate of Soda.— To make stannate of soda, 
proceed thus. Melt together 2 parts of caustic soda and 
1 part of finely powdered tinstone (native oxide of tin). 
Add to the melted mass a small q uantity of hot water, allow 
to settle, and pour off the clear liquid ; this can be evapor- 
ated to form the liquid stannate. On further evapor- 
ation the liquid will commence to crystallise, and after 
cooling the crystals may be strained off, washed once or 
twice with a little water, and dried. The liquid poured off 
from the crystals should be evaporated to dryness and 
added to the next melt ; the part insoluble in water may 
also be added so that there may be no waste. Tin 
crystals (stannous chloride) are formed by boiling tin 
with hydrochloric acid until no more will dissolve, and 
then evaporating and cooling the solution ; the tin 
ci-ystals will then separate out. 

Testing the Speed of a Camera Shutter. — A 

method ot estimating the speed of a camera shutter 
is as follows. Attach to the side rim of a bicycle 
wheel a piece of tinfoil. Invert the bicycle, place it 
in the sunshine, and fpcus this wheel sharply. Put 
a plate in the camera ready for exposure, and set 
the shutter at its lowest speed, using as large a stop as 
possible. Revolve the wheel so that it makes one revo- 
lution per second, or fifteen revolutions in a quarter of 



oil with boiled oil. If a tint is wanted, work In the 
requisite quantity of pigment ground in oil ; ochre 
for cream, Venetian red for salmon, middle Brunswick 
green for pale green, ultramarine for grey, burnt sienna 
for a reddish buff. Por dark coloured paints, replace the 
white-lead with a similar quantity ot pigment ground 
in oil, and use more boiled oil, or else add a little good 
oak varnish. 

Determining Superficial Surface of Steam Pipes. 

—The rule most usually adopted for detei-mining the 
number of square feet of heating surface of diiferent 
sized steam pipes is to calculate that a foot leugth 
of 4-in. pipe has a superficial,, i.e. square, foot of 
sui'face. Then the areas of other sizes can he readily 
estimated. A 1-in. pipe, for instance, has one-fourth 
of a square foot ot surface per foot run, or a square 
foot to 4 ft. run. This would also apply to bends, 
fittings, and other hot parts of the installation. These 
calculations are based on the interior diameters of 
pipes. Often the exterior is taken, by which a li-in. 
pipe, I ft. long, would be said to have half a square foot of 
surface, because it is of 2in. exterior diameter (nearly). 
This, however, is not a correct way, for it gives a certain 
size of pipe a variable super surface according to the 
thickness of the material ot which it is made, whereas 
the thicker material would deoi-ease heating' elficacy 
rather than increase it. 

Manufacture of Condensed Milk.— In making con- 
densed mUk, milk is mixed with sugar and then evapor- 
ated by steam in a vacuum pan, in which a reduced 
pressure may be kept in order that the milk may lose its 
water at a much lower temperature than the boiling 
point under ordinai-y pressure. The temperature em- 
ployed is about 100 deg. P., and the vacuum is kept as 
good as possible. The plant required consists of one or 
more vacuum pans, a boiler for supplying steam and fo' 
pumping, suction pumps, etc., and canning outfit. 



26 



Cyclopaidia of Mechanics. 



Making Sugar Fign res.— Sugar flgurea are made by 
placing about 2 lb. of sugar in a ran and adding barely 
sufficient water to cover it and a little cream of tartar ; 
melt down by a gentle heat, and boil to the degree known 
a8 " ball," i.e. about 250° F. Rub the pan briskly with a 
etlck until the sugar thickens, then fill the moulds as 
quickly as possible through a funnel. Objects that are 
flat on one side may be moulded in starch powder, 
shaped objects in plaster-of -Paris moulds, while laige 
objects are usually made hollow, the moulds being filled 
with the sugftr, and the unsolidifled portion being poured 
out after a few minutes. 

Hot BOX for Pboto Negatives and Lantern Slides. 

—An aid in varmshing lantern slides made from negatives 
or in varnishing photographic negatives themselves is 
Dlustrated by Figs. 1 to 5, the letter references in these 
figures being similar. It is usually advised to heat the slide 
before a fire or lamp before flowing the varnish on and 
off ; in too many cases this means unequal heating and 
burnt fingers, with this hot box it is only necessary to 
lay the slides on the top, fill the box with water (boiling 
or cold) , and light the spirit lamp, and in a short time the 
slides will be heated equally all over. After varnishing, 



out one on the other side, and both together are use- 
less without holes through the cross walls to allow of 
a through draught. If the joints of the floorboards are 
open, a little ventilation may be afforded by currents of 
air finding their way through. If the upper face of the 
boards is expoaed, the fungus cannot thrive on itj its 
ravages will be confined to the lower side of the floor, 
and it will make its way through the boai-ds slowly. 
Obviously that part of the floor which is covered with 
loose-textured carpet has the better chance of holding 
out, but that which Is covered with oilcloth, and thus 
cut off above and beneath from all supplies of fresh air, 
has everything against it. As regards the moisture, 
the fungus is greedy for this, although it has to take 
its supply in very minute quantities from the air or 
from objects with which it is in contact. _ So much 
moisture, indeed, does it succeed in taking in that it 
has to discharge an excess, which hangs on its surface 
in clear sparkling drops, hence its name, Meruleus 
lachrvmwns (laohrymans being the Latin for weeping). 
The remedy is to remove the whole of the floorboards, 
joists, and other timbers. Every vestige of fungus In 
any form should be scraped or brushed off the brick 
or plaster work. Examine the skirting, and remove 




Pig. 2 FIG- 5 

Hot Box for Photo Negatlres and Lantern Slides. 



they are left on the top untU thoroughly hard and di-y. 
The box consists of eight pieces of wood screwed together, 
supporting a zinc box with an iron top. The front and 
back pieces A and B are each 17 in. by 6 in. by Jin. The 
two side pieces C and D are each M in. by 6 in. by J in. These 
four pieces are mitred at the angles, chamfered on the 
top edge, and screwed to the angle pieces E, P, G, and H, 
each 4 in. bjr lin. by lin., on which rests the zinc box. 
The front piece has an opening cut in it to admit the 
lamp L, and the back piece has two pieces cut out to 
admit the water inlet J and the steain vent K. The hot 
box is 15 In. by 12 in, (this allowing i in. space between It 
and the wood) and 2in. deep. It is made of stout zinc 
with an iron top iVin. thick soldered on, forming a level 
bed for the slides. The water inlet discharges on the 
floor of the box, and the steam vent is taken from under 
the top plate as, shown. Steam issuing from the water 
inlet indicates that more water is needed. This box 
will take one do^en lantern plates and, as has been 
stated, is equally as well adapted for use in varnishing 
ordinary photographic negatives. 

Dry Rot In Floor Boards.— The coi-jditions most 
favourable to the germination of the spores of the dry 
rot fungus and to Its subsequent growth are (1) a still 
atmosphere— no draught, (2) a little moisture— not too 
much, (3) a little warmth, (1) a little ammonia. An 
air brick on one side of the house is of no use with- 



any that has any suspicion of the growth on it, even 
the white mould. Clear the ground and take off an inch 
or two of its surface to ensure getting rid of every trace 
of the disease and its spores. In some cases an appli- 
cation of fresh limewash to the surface of the walls 
has prevented further development. Vitriol hUs also 
been applied with ^ood effect. If not too expensive, 
cover the ground with hot lime 'concrete. Break holes 
through the cross wall, preferably at the ends, as the air 
is apt to become stagnant In' the corners. Put at least 
one air brick at the hack of the house, and above all 
things see that the new timber used is not Infested with 
incipient dry rot before it is used. 

Action of Steam In Locomotive. — A locomotive 
usually, though not always, has a pair of simple 
engines. These act as ordinary horizontal steam 
engines, steam being admitted and cut off accord- 
ing to the notching-up. It then expands to fill the 
cylinder, pushing the piston before it. Just before 
the end of the stroke the exhaust port opens and 
steam is exhausted from one side of the piston up the 
chimney, its pressure, which now is a back pressure 
or resistance, falling and the piston being pushed by 
fresh steam in the opposite direction. The motion 
of the piston Is transmitted through the piston 
and connecting rods to the crank, and thence to the . 
wheels. 



Cyclopaedia of Mechanics. 



27' 



A Simple Level.— 'With the simple level illustrated 
the proper grade and levels for drains, ditches, road- 
ways, concrete flooi's, foundations for houses, and 
for bridges, etc., can be laid out. In fact, all sorts 
of levelling can be easily and readily done -with 
this Instrument. Pig. 1 shows an elevation of the 
complete instrument; A is a builder's ordinary level 
fitted with 'a pair of Stanley's improved level sights 
BB. The level is placed on a table c that can be set 
level by means o£ four thumbscrews D and sighted in 
any direction. In the figures, B is a triangular block of 
hardwood to which are fastened the parallel plates 0, and 
also the three legs by three screws G; H is a small 
brass eye screwed into the centre of the underside of 
the triangular block to suspend a plumb-bob if it should 
be required to place the instrument over a point. Fig. 2 
is a section showing dimensions of the parallel plates. 
The top plate should be of two pieces glued and screwed 
together, cross-grained to pi'event twisting. In the 
centre is fastened, by means of a brass screw, the ball J 
ior the ball-and-socket joint. In the centre of the top 
piece of the bottom-plate a hole is made to fit the ball to 




Fig. 1 
A Simple Level. 

form the socket of the joint. Before glueing the two 
parts of the bottom-plate together, the triangular block 
of hardwood (3iin. long with 2-in. sides) must be screwed 
to the bottom-piece on the under-side. The thumb- 
BorewB on the lower plate are equally spaced Jin. from the 
outer edge. On the under-side of the top-plate over the 
point of the thumbscrews, and for them to bear against, 
small brass plates K K, Fig. '2, should be fixed. The 
levelling stafi: can be made by painting the divisions on 
a strip of f-in. board, or, if preferred, papers printed with 
the dfvisions can be obtained and pasted on the board. 
The instrument is set up and used in the same way -as 
an ordinary dumpy level. 

Cod Liver Oil Emulsion.— To prepare an emulsion of 
cod liver oil, triturate together in a mortar 2 oz. of gum 
arable and 3oz. of water, then add 802. of cod liver oil -, 
slowly beat the whole together until a smooth cream is 
formed. 'Now dissolve 128 gr. of hypophosph/te of lime 
d.nd 96 gr. of hypophosphite of B,oda in 3 oz . of water, 
and beat this up with the other Ingredients. To disguise 
the flavour of the oil, add 1 oz. of sugar syrup (1 part 
sugar to 1 part water) or glycerine, and a few drops of 
essence of almonds ; mixthese with the other ingredients 
as before. 

Working and Polishing Ebony.— Ebony must be 
selected for colour, grain and texture first, as these vary 
very much ; the cuts near the bark or outside surface 
often contain sand and other foreign substances which 



dull the edges of the tools employed. Ebony may be 
turned in the lathe, using, for small work, two gouges, 
one for roughing out and the second for finishing. The 
tool is held above the centre, a high speed is employed, 
and light cuts are continually taken, the finishing cut 
leaving a dead polish which only needs a handful of 
turnings held against the work whUe' revolving to 
brighten it. A piece of blanketing with a few drops of 
linseed oil finishes the work. More elaborate forms of 
eboii.7 work are cut with a revolving drill in the lathe ; 
and there is also an automatic lathe for turning out 
handles in quantities. Ebony in the flat Is first sawn 
with a fine circular saw into slabs or veneers. Further 
shaping may be done with a hand or power fret-saw. 
The finishing is done by fine rasping and filing, ahd the 
polishing is began by scraping with a sharp knife or a 
proper scraping tool, always scraping in one direction : 
the polishing is completed by dollying off on a felt 
dolly driven by power, the dolly being kept moistened 
with linseed oil. 

Making a Wringing Machine.— A simple wringing 
machine can be made in this manner. Obtain two 
indiarubber rollers mounted on spindles ; remove the 
cogs, as these are not used. Also obtain twd slotted 
plates as A (see sketch) , made from IJ-ln. by tVI". i™" ! 
the slots in the plates must be of a size to fit easily 
on the spindles of the rollers, the distance apart being 
regulated by the diameter of the rubber. Also make two 




Making a Wringing Machine. 

springs from 1-in. by tj-in. steel, shaped something like 
B. Two clips, as C, will also be wanted ; the top part 
must be drilled to take a bolt D, a corresponding hole 
being made in the two springs. One leg of each of the 
clips must also be drilled and tapped, and a thumbscrew 
fitted, as E. To fit the parts together, first place the two 
roller spindles in the slots in plates, then spring on the 
impression springs, one on each end. Now measure the 
distance from centre to centre of the two springs, and 
drill a piece of flat iron so that it will fit between the 
springs and the clips, as shown at ]? ; this will keep the 
springs rigid sideways. The clips with thumbscrews are 
for fixing the machine to the washtub, and, being fixed 
by one bolt onljr, will swivel roilnd so as to be used at 
either angle. One of the roller spindles should be 
squared or threaded for a winch handle. All the iron- 
work must be well painted or given two good coats of 
bath enamel. 

Bending and Canvassing Landau Panels. — 

It nailed fiat across the boot-side, with the top edge 
rounded down, or overhung to form a bead in the neck, 
the panel should be bent and canvassed before fixing. 
This must be done very carefully, or the panel will split. 
To canvass a panel after it is bent, place it on a wide 
board, round side up, and drive in a draw-bove pin at 
each outside corner ; this will prevent the panel s&g- ' 
ging'inthe centre, which would split it. If the panels 
are boxed in fliish, canvass them after they are pinned 
in. Quarters and back panels should be canvassed a 
day or two before they are wanted ; there is then less 
danger of breaking them when fitting them in the 
grooves. This only applies to panels with a sliRht single 
sweep i where there is a return or chair-back sweep they 
must be canvassed after they are in. 



28 



Cyclopaedia of Mechanics. 



Noise in Hot-water Tank.-It is sometimes the case 
that a hot-water apparatus worlts well until the water 
reaches the boiling point, when a rumbling sound at the 
tank is heard. This noise is merely tlie sound ot the water 
boiling. The remedy is to regulate the boiler damper so 
that the water sball not boil. "When the noise occurs, it 
can be silenced by drawing off some water at one Sf the 
hot-water taps. This causes cold water to flow into the 
tank and reduce the temperature. The fact that water 




the first as small as possible at the tapered end of the 
mesh, the last two being worked loosely at the broad 
end i the first stitch ol the second row will then be nearly 
regular in size, and In the third row all will be even. But 
in this row, if the net was commenced on six meshea 
only, stitches must be added ; to do this, work two 
meshes on each loop ot the former row, or two on every 
other loop, according to the shape ot net required. In 
this way add meshes in any row where it is desired to in- 
crease the diameter. It is not often wished to decrease 
the diameter of a round net, but if required to do so, 
pick up two meshes on the needle at once and hitch 
together in one ; each time this is done one mesh less 
will, of course, follow in the succeeding row. 

Manufacture of Calcium Carbide. — Calcium car- 
bide may be made by heating an intimate mlrtui'e 
of finely divided coke or carbon and lime in an electric 
furnace, using a current ot from 4,000 to 5,000 amperes. 
The furnace used by Willson in America consists of an 
outer coating of firebrick lined with carbon or 
graphite, a tap hole being placed near the bottom ; the 
furnace is covered with carbon plates, through which 
passes a thick carbon rod reaohiiig nearly to, but not 
touching, the bottom of the furnace ; the carbon rod and 
the inner carbon layer are connected to the dynamo. 
1,2001b. ot fine coaldust and 2,0001b. of quicklime yield 
2,000 lb. of carbide in twelve hours. 

Centrifugal Pump. — Herewith are dimensioned 
drawings of a centrifugal pump designed to lift 
150 gal. per minute at 20 ft. head. To enable the 
volute to be correctly foiTued the case Is in two 
halves. To avoid end thrust and to ensure an even 
balance ot the disc, the infiow takes place on each 
side, each inlet having a diameter of 3 In. Pig. 1 is a 
side elevation and Fig. 2 one half of the case showing 
the depth of the volute and dlpc with angle of vanes. 
The volute, to obtain a good flow, must Increase 
evenly to Its discharge. The discharge ^ipe should In- 
crease In area to reduce the velocity considerably. The 
flange of the casing Is lln. wide, drilled to takej-in. 




-r- 



Centrifugal Pump. 



has a tenrlency to boil Indicates either the use of a more 
powerful boiler than the apparatus requires, or want of 
attention to the damper. The latter is the more probable 
fault, causing the boileri to become overheated and fuel 
to be wasted. 

Making a Bound Net. — In netting a round net, 
the loop upon which the first meshes are made can 
be afterwards tied up tightly to form a bottom. Or 
the first meshes can be cut away, the short cut 
ends pulled out through the inner bights of the second 
row (that is, the now inner row of whole meshes), 
and a grommet worked if a circular hole Is wanted ; 
or the ends can be drawn together and tied with 
a separate piece of string. To prevent crowding ot 
meshefl at the bottom ot a round bag it is usual to com- 
mence with about six meshes for the first row, making 



bolts. The diameter of the disc is 9 in., and Is arranged 
for six vanes, having an angle ot 80" at the cire^aifer- 
euoe. The shaft is J in. diameter, and the approximate 
speed ot disc is 650 revolutions per minute. Kg. 3 Is a 
section showing side Inlets, disc, and brackets, and 
Fig. i is a section ot half of the disc showing dimensions 
of the vanes. 

Glazing Clay Tobacco Pities.— A simple lead glaze Ib 
generally used for clay tobacco pipes. The following may 
be taken as examples, (a) Ilead oxide (litharge^ , 45 parts : 
sand, 35 parts j common salt, parts, (b) white lead, 53 
parts i Oornish stone or felspar, 16 parts i white flint glass, 
5 parts. The glaze may be melted In a crucible, ana the 
stems ot the pipes (which should have been previously 
burnt) dipped in. For green colour, use 5 per cent, of 
oxide of copper -, for red, 5 per cent, of red oxide of iron. 



Cyclopaedia of Mechanics. 



29 



PoUshing Turned Wood.— Soft woods may be turned 
so smooth in the lathe as to rectuire no other polishing 
than that produced by a few line turnings or shavings 
,of the same wood applied while revolving in the lathe. 
Mahogany, walnut, and some other woods may be 
polished by the use of a composition made by dissolv- 
ing by heat so much beeswax in spirit of tui-pentine 
that the mixture, when cold, shall be of about the 
thickness of honey. Or instead, dissolve 1 oz^ of san- 
daraoh In i pint of methylated spirit, and mix the 
solution gradually with loz. of beeswax in sufficient 
turps to make it into a paste. Apply with a woollen 
cloth whilst the work is still in motion, and polish 
with a soft Unen rag or chamois leather. The work 
thus treated should have a highly varnished appear- 
ance.- Hard woods may be readily turned very smooth, 
and fine glasspaper will sufgce to give them a very good 
surface; a little linseed oil may then be rubbed on, 
and a portion of the turnings of the wood to be polished 
may then be held against the article whUe it revolves 
rapidly. By this means a fine gloss will be imparted. ' 

Scenting Powder.— To perfume a .powder with otto 
of roses, place it in a mixing machine, i.e.. a revolving 
cylinder or ban-el provided with ribs internally. Spray 
the scent into the powder and set the machine in motion 
until the scent has been disseminated through the whole. 
To disseminate the sc6nt better, dissolve 1 part of the 
otto in 6 parts of spirit of wine, and use the mixed 
essence in place of the pure oil. 

Making Silver Mounts for Tobacco Pipes.— In 

making an ordinary pipe mount, a plate of silver 
has to be prepared to fit .tightly round the two pieces 




be trued on the triblet previously mentioned with a 
smooih-faeed mallet. The work could be more easily 
done in a lathe, which would also be useful in the subse. 
quent polishing. If the metal is so thin that the triblet 
and mallet or hammer ai e of little service, use a ribbed 
burnisher (Pig. 2) , with which it is quite possible to rub 
the thinnest of collars true and smooth. The burnisher 
may be from Tin. to 10 in. long, lin. wide, and Win. 
thick, and can be made from an old flat file. The ribs or 
ridges should be quite smooth, and should be of the size 
shown in Fig. 2. When the mount is in shape, and fits 
the pipe, it will have to be smoothed and polished. Ee- 
move hammer marks, etc., by filing, and not by the use 
of glasspaper or emery-cloth ; by the latter means the 
corners are rounded instead of being left sharp. The 
next thing is to polish the mount. The principle under- 
lying most polishing processes is a simple one. It is the 
application by friction of abrasive materials in stages of 
gradually increasing fineness. It that is understood, it 
wUl be an easy matter to make shift with materials that . 
may be handy, though those mentioned here may be 
obtained in small quantities at oilshops and of dealers 
in jewellers' materials. As the mount to be polished 
may be thin, and therefore likely to get out of shape, a 
piece of wood should be fitted to it, and this will both 
support it and allow it to be handled with comfort. 
First is used a stick of water-of-Ayr stone with water, a 
damp sponge being employed to remove the mud-like 
stoulngs as they are produced. This is followed by 
pumice powder and oil, and this by crocus and oil (or 
rotten-stone or Tripoli powder and oil). These may be 
applied by means of buffs made by glueing strips of buff 
leather to pieces of wood. Next softly brush the mount 
with damp whiting, and then wash it in hot soda and 
water to remove all the contained grease in the polishing 
materials. The final'polish is given with rouge, applied 
by a buff at first, and then by the palm of the hand or 
the ball of the thumb. Wash off all rouge, and the 




Making Silver Mounts for Tobacco Pipes. ' 



of the pipe to be joined by its means. The easiest way 
to obtain a pattern of this plate is by wrapping a 
piece of smooth paper round the place on which the 
mount is to go, and very carefully cutting all the surplus 
away with a pair of scissors until one thickness of the 
paper is all round the pipe. If this is done carefully and 
due attention is paid to the straightness of the solder- 
ing seam and of the ends, the silver can be out to fit 
exactly. The plate must be flattened, and then turned 
up into a tube quite free from bruises or kinks. For 
this is required ,a " triblet," which is a tapering piece of 
smooth round iron or steel; a bending block is also 
Tsquiredl A mallet also may be necessary/ if the silver 
is thick ; thin metal will come up by the pressure of the 
hand almost, and may be worked with a pair of half- 
round pliers in place of the block and mallet. With a 
' knife or a scraper made from a three-square file, make 
- the edges to be soldered together quite level and true 
with each other ; see that no burr from the file is left 
on the metal when tying with wire. Should the mount 
be long, it is desirable to file small nicks in the edges 
that form the seam a a (Fig. 1) , so that the solder may 
hold better ; the seam will not be so likely then to open 
during the subsequent operations. When fitted, the tube 
is tied with iron binding wire so that the edges remain in 
the proper position whilst soldering. Thin wire should 
be used, as thick wire on cooling and shrinking may 
bruise the work. The tying of the wire is not a difficult 
job, but with a veiT tapering mount means have to be 
taken to prevent the binding wire slipping down (see 
Fig. 1) . In soldering, which is the next process, brush the 
flux on the edges to be united, which previously should 
have been scraped clean. The flux is borax rubbed up in 
-water. Lay some pallions (small pieces) of silver solder 
along the seam, and with a gentle heat from the blowpipe 
flame evaporate aU moisture. Then, if the soluer has not 
been shifted, apply the full heat. When cold, pickle in a 
mixture of 1 part of sulphuric acid and 40 parts of water, 
and file off any pieces of unflushed solder. The mount 
now is sure to be more or less out of shape, so It has to 



mount is then ready for fixing on. It is important in 
using the rouge that the hands, rouge, and everything 
by which the mount is touched be quite free from grit. 
Jewellers' i-ouge is not that sold as face powder, but is 
peroxide of iron specially prepai-ed. The best quality 
has a red colour having a decided purple tinge. Kouge 
varies in colour from the one mentioned to a deep red. 

Ball Clay for White Enamel Body.— Ball clay used 
in the pi-eparatiou of white enamel body may have 
a composition of Cornish stone, 40 parts; Cornish 
clay, 10; and blue clay, 20. , Or Cornish stone, 80 
parts ; Cornish clay, 20 ; blue clay, 40 ; and flint, 20. 
Or Cornish stone, 100 parts ; Cornish clay, 20 ; blue clay, 
18 ; and flint, 40. Or Cornish stone, 30 parts ; Cornish 
clay, 10 ; blue clay, 17 ; and flint, 8. The colour can be 
rendered bluish-white by the addition of a little cobait 
blue. The non-fusible materials added to the glaze are 
barytes, bone ash, and oxide of tin ; the latter is put 
into nearly all enamel glazes. The clays are mixed with 
excess of water, passed through a fine sieve, and then 
boiled down to a paste. Here are recipes for white 
Blazes. White glass, 100 parts ; white sand, 60 ; salt, 40 ; 
litharge, 120 ; and oxide of tin, 60. Or lead and tin -ashes, 
44 parts ; sand, 44 ; soda, 2 ; common salt, 8 ; and red- 
lead, 8. 

Pressure of Water.— A pressure is often stated as 
being equal to so many inches of water. If the height 
of water were H in., the expression would mean a pres- 
sure equal to that caused by a column of water liin. 
high, or, in other words, the weight of such a column. On 
the square foot this will mean a pressure of 7'794 lb. ; on 
the square inch, tI, of this, or 'OoUb. The higher 
pressures are usually measured by a Bourdon or other 
pressure-gauge ; the light pressures are ascertained by 
inserting a tube and measuring how many inches of 
water in the tube are required to balance the pressure 
—thus the terra, a pressure equal to so many inches of 
water. 



30 



Cyclopaedia of Mechanics. 



Cement for Jointing Hot-water Pipes.— Cement tor 
making joints in hot-water pipes contains HO to lUO pai-ts, 
by weight, of iron borings twhioh must be pounded ll 
coarse) , 2 pai-ts of flour sulphur, and 1 part ot jjowdered 
sal-ammoniac. Tlie ingredients must be well mixed and 
moistened with water, this being done Irom half an 
hour to two hours before use, according to the weather. 
The joint is first caulked a little more than half 'lull of 
yarn, then finished with the prepared borings. The 
borings must be caulked in carefully, or the socket will 
be split as the joint sets, for the borings expand a 
Little in setting. 

Faint Blistering on Front Door.— The blistering of 
paint is caused by the presence of water either In the 
paint or in tlie substance to which the paint is applied, 
greatly aggravated by the action of the sun upon the 
door. The old paint should be burned off with a spirit 
lamp, and the surface of the door well rubbed down with 
glasspaper. Then give a priming cpat made of 21b. of 
white lead, .3 oz. of red lead, and 3 oz. of yellow ochre 
(note that the red leadisadi-ier). Thin with one-third 
raw oil and two-thirds turpentine. Finish in any desired 
colour, using as little oil as possible, or turpentine 
Instead of oil. Varnish on a dry day with a good varnish. 
It is better not to buy the varnish from an oilshop. 
Clean all water out of the brush before painting ; a dirty 
brush — i.e. one with water in it— is often the cause of 
I paint blistering. 

Gilding and Silvering Leather. — Gum mastic in 
fine powder is first dusted over the surface to be 
gilded. An iron or brass tool bearing the design upon 
its face is then heated to the proper temperature 
and gently pressed on a piece of leaf gold, which 
adheres to the tool. On pressing the tool lightly 
to the surface to be gilded the mastic softens and 
retains the gold. The loose gold and powdered mastic 
are then brushed olf . Gold leaf will adhere to leather 
without mastic, but not so firmly as with it. To apply 
tinfoil or silver leaf, place on the part of the leather to 
■be covered some size or white of an egg, and after press- 
ing down the metal aid drying. Wash over with gold- 
colour lacqtier. The following tools, etc., will be re- 
quired. A long,' thin knife, sti-aight, and not too sharp ; 
a wide thin brudh, with camel hair about Sin. broad; a 

Ead for cutting the gold leaf, and a dabber, a small soft 
all of cotton-wool enclosed in a square ot muslin with 
its edges drawn together and tied to form a handle, and 
wheels and stanips of the shapes required. 

Cleaning Briinze Chandelier. — To clean a bronze 
chandelier that is con-oded by damp, take the chandelier 
to pieces and carefully remove all pins, screws, and 
other iron parts. Then place about ilb. of potash 
in Igal. ot water, and in this boll off all the old 
lacquer. Allow the various parts tp remain in the 
solution for about twenty-five minutes ; then take them 
out and well wash in clean cold water. They should 
then be dipped in aquafortis, and allowed to remain 
sufBciently long to become bright. Each part should be 
held in the acid bath by means of a copper wire twisted 
round, or by holding with a small pair of brass tongs. 
Then well rinse in several changes of clean cold water, 
either by having several vessels or by well rinsing in 
running water. Transfer to the sawdust tub, dry, and 
relacquer. 

Making Warner Wheels,— Procure a pair ot Warner 
stocks and set of spokes to match ; these are sup- 
plied with the ii'on band mortised the' exact size of 
the bottom part of the spoke just above the shoulder, 
which is sunk or housed in lull i in. from the face 
of the iron b^nd, the shoulder of the spoke resting 
on the wood centre ot the stock. To fit the spokes 
into this part, the mortises already made must be 
eased out to ensure a good fit to the tenon of the 
*poke. Before driving the spokes into the stock, clean 
off the front end of the stock quite level, and fix with a 
coach-screw, dead in the centre, a strip of wood called a 
set-stick ; this must be perfectly straight and parallel, 
2 in. wide by 1 in. thick, and a little longer than the 
spoke. Measure the distance from the front of a 
mortise to the set-stick. In the set-stick, at the height 
of the shoulder of the spoke, bore a hole, and insert a 
piece of cane or whalebone, keeping it as much shorter 
than the distance from the mortise at the bottom as the 
dish required in the wheel. In wheels of this description 
J in. is Bufflcient when made, as they go more in tyreing. 
Drive all the spokes in, so that they touch the peg in the 
set-stick. To get the tongues all alike, plane a small 
piece of panel board to such a width that when held 
against the inside of the set-stick the opposite edge of 
the board comes on the spoke full i in. Mark all round 
by this. Now set off the size of the tongue with com- 
pafises, and cut down, sawing the shoulders on the front 
and back only, pulling out the sides with the draw-knife. 
Tn large firms, the tongues are made with hollow augers. 



which cut a square shoulder right round the spoke ; but 
this method is not so strong as that described above. In 
cutting in the felloes or rims, see that the joints are 
square and true, and bore the dowel holes parallel with 
the face of the felloe ; also bore all the holes for the 
tongues exact, as when they are bored through at 
different angles it is impossible to get a true face on a 
wheel i undue strain is also put on the tongues of the 
spokes, so that they soon break off short at the 
shoulder. 

Darkening Cement for Pointing.— For darkening 
C'Jment to be used for pointing brickwork bricklayers use 
smithy ashes, which can be procured from any blacksmil h . 
The ashes should be ground or crushed to the size of sand 
(not crushed to powder) and used instead of sand, or some- 
times a small quantity ot sand is mixed with the cement 
and cinders. The wearing qualities of the cement 
are not Improved by the use of cinders. Lampblack is 
occasionally used as a colouring agent, and when it is 
used sparingly the wearing qualities ot the cement are not 
lessened. 

Setting Out the Sides for a Step Ladder.— In set- 
ting out the sides for a step ladder, first set up the 
vertical height C B (Fig. 1) to a convenient scale, and 
divide for the number ot steps required (the usual dis- 
tances, as shown at F, Fig. 3, being from Tin. to 9 in.). 




Setting Out the Sides of a Step Ladder. 

Next set off the splay AB (Pig. 1). Join A to 0; this 
will be the pitch of the sides. -Draw a horizontal line 
and set a bevel to this and the pitch llhe as shown 
at K (Fig. 1). Now draw a horizontal line D E, then AE 
will be the distance apart of the treads measured along 
the edge of the strings (sides). Set a pair of compasses 
to this distance, and step them along as near as possible 
to the outer edge of the string and mark off with bevel as 
shown at Fig. 2. nig. 3 shows the visual section ot steps 
which are often wedged into the housing of the string 
as indicated at "VV. This would have to be allowed for as 
shown at i, 5 (Fig. 2) . 

Bricks for Cupola of Furnace.- For lining cupolas 
for blast furnace or other cupreous slags, nothing is 
better than Dinas bricks unless it be ganister bricks 
as made at Lowood near Slietlield. The only difference 
between the two is the quantity ot silica contained in 
each. A good Lowood brick has assayed out at the 
following proportions: Silica, %'i; alumina, 1; lime, 
I'25 ; sundry oxides, 1'35 ; while a best Dinas brick from 
Wales assayed out as follows: Silica, 9.5'75i alumina, 
•i ; lime, 3 ; sundry oxides, 'So. Ganister bricks do not, 
on cooling, crack so quickly as Dinas bricks, because 
Dinas bricks, having a higher percentage of silica, are 
practically Infusible and unaffected by the great heat. 
The bricks, eitlier Dinas or ganister, should be set in the 
very thinnest ot ganister cement, the xisual plan beln^ 
to dip the brick in yery thin cement, and when the work 
is finished to slurry over the surface with thin cement. 



Cyclopaedia of Mechanics. 



31 



Determining Discharge of Water through Pipe.— 

The watei' velocity in feet per second corresponding to 
a given pressure can be calculated by multiplying the 
square root of the pressure in pounds per square inch by 
12'19. The velocity being thus obtained from the effective 
pressure, multiply It by thfe area of the pipe in square 
feet and by 6'23 to determine the quantity discharged in 
gallons per secpnd. 

Lines on Picture Mounts,— There are several methods 
of placing gold lines on mounts tor pictures. First 
make small pencil dots where the lines are to end. 
If gold powder is used, make the lines with a strong 
solution of gum, and when this is " set " breathe gently 
on the lines, and dust on the powder. White lines ai'e 
made by means of white ink, a heavy mixture of Chinese 
white. A common pen kept well charged will answer 
admirably as a means of applying the ink. 

Putting Felloes on Wheels.— Herewith la an illus- 
tration of a device for pulling towards each other the 
spokes of cart and carriage wheels.. This dispenses with 
the lever and other tools used in some methods of doing 
this work. Having fitted the spokes and holed the feUoes 
to suit, tie the ends of about a yard of tough cord about 
tin. in diameter to form a ring, which is slipped over two 
spokes, and then twist this with the handle of a hammer 
until the spokes come to position. Then by a piece of 




angle of 75" with the vertical. The tables on the in- 
strument show the place of the centres of the arcs of 
fianks and faces upon the scales for wheels with teeth 
numbering 12 to loJ, and foi- racks, the pitches varying 
from 1 in. to 3 in. Other pitches may be found proportion- 
ately j thus, lor a J-iu. pitch, take out halt the tabid 
value for a pitch of 14 in. To use the instrament, one halt 
the pitch is marked along the pitch circle of the wheel 
to be set out at each side of a radial line. From the two 
points thus found radial lines are set off. Then the 
sloping line ot the instrument is placed so as to coincide 
with one radial line, with the edge ot the scale over the 
point on the pitch circle. Then consult the table of 
' centres for flanks ot teeth; the number in the table, 
which varies with the pitch and 'the number of teeth, 
shows the point on the scale line above at which the 
centre of the curve tor the flank ot the tooth Is situated. 
Similarly for the centre of the face ot the tooth set the 
sloping line on the other radial line with on the pitch 
circle. Then the table shows the position of the centre 
on the scale measured downward from 0. 

How to Make an Knlarglng Lanteru.— Below are 
particulars on the construction ot an enlarging 
lantern. Make a baseboard A, and to this attach the 
frame B of three sides, with a circular opening' in 
front tor a condenser at B'. Above and below this opening 
fasten grooved rails P and G to take the sliding negative 
frame. Join up tour mitred pieces to form a frame K, 
and make the lens-board P. Connect the two - with 
bellows. Bore a hole through K and P to take a brass 
rod M. Fasten K to 1? and G, and tlx a turn-pin of stout 
wire at N to clamp the rod M. Fit up the negative frame 




Putting Felloes on Wheels. 



lath, as shown in the figure, keep them up as long as 
required; by removing the hammer and undoing the 
running knot the appliance is ready for another pair. 

Removing Paint from Floor Boards. — Freshly 
slaked limewash, to each bucketful ot which is added 
at least 21b. ot common washing soda, makes a good 
ptiint remover, li should be applied by means of 
common fibre brushes— not bristles ; several applications 
may be necessary to remove the paint. The latter should 
be removed by scraping when so'lt, then swillefl olf witii 
plenty of clean water, and finally brushed oyer with 
common malt vinegar. It is doubtful whether, after this 
treatment, the boards will be sufficiently clean to be left 
as white without bleaching. For the latter, frequent 
applications of oxalic acid— 2oz. to Ipt. ot water— will 
generally suffice. Partially to remove the black so as 
to gain an old oak effect, try equal parts of turpentine 
and methylated spirit. If this can be made hot with 
safety it has greater penetrating power. Liquid ammonia 
is also efteotive, but is best handled if diluted with an 
equal bulk ot water. 

Willis's Odontograph.— The Odontograph, invented 
in 18:i8 by Professor 'WiliiB, has been used to determine 
the radii of arcs of circles that shall approximate to the 
epicycloidal and hypocycloidal curves which should be 
used if perfect forms are wanted for the teeth of 
wheels. The Instrument consists of a scale and a 
table. The first may, be set out as follows on a piece 
of cardboard about 14 in. high by Ik in. broad. At 
the right-hand edge, and about 2J in. from the base, 
take a point. I'rom this point divide the edge into 
lengths ot «in. and number the divisions 10, 20, 30, 
etc., both above and below the point first marked, 
which should be numbered 0. Then subdivide each 
4-in. division into ten equal parts, and from the point 
first marked (0) set off a line towards the base at an 



A SG"Y"R a 

An Enlarging Lantern. 

to go in S, with ah opening 4 in. by 3 in. and 4 J in. by 
3tin. rebace. Sink the rebate deep enough to allow of 
the turn-buttons which hold the negative coming ilush 
with the surface. The condenser Q is fitted in a block R. 
Inside B is a second frame X of iiussian iron. Tlie holes 
- in this (see dotted Hues) are not opposite those in B, so 
that ventilation withoub outside light is secured. Short 
rails are fitted on A, between which ttie lamp with refiector 
runs. A four-wick paratfinl^imp will be best. Fit a door 
H. The base is hinged at Y. This lantern could also 
be used as a magic lantarn. 

Repairing Broken Rib of Ivory Fala. — The mend- 
ing ot the end rib ot an ivory tan containing a 
fracture about an inch long, is a rather difficult job, 
as the joining up must be done from the back. Pro- 
cure a thin veneer ot ivory 2 in. long and rather 
wider than the rib of the tan. Scrape the surface of 
the veneer and the back of the fracture and fasten 
together with cement. When set, dress off the sliarp 
edges with a file, and reform the edges of the carved 
surface' by filing aad" scraping, taking particular 
notice that the strengthening piece does not cause 
the fan to bulge when shut up. It the rib is saw- 
pierced as well as carved, the holes may now be 
drilled to admit the saw, which must be carefully worked 
round the original piercing. A more substantial job, if 
the fan is valuable, would be to procure a veneer of 
African ivory about Jin. thick, the carving and dressing 
of which would bring it dowu to ^, in., the relative thick- 
ness of the end ribs. For convenience of handling, this 
veneer may be tacked down by the four corners on a flat 
piece of wood. The design may now be drawn on the veneer 
with pencil and the pattern cut with sharp gravers sui-h 
as engravers use. To get the stuff out cle^n and smooth, 
each out , must be repeated till the proper depth is ob- 
tained. If the work is merely an incised pattern, filled in 
with either black or red-pigment, the engraving is done 
with a well-whetted lozenge graver, the work being 
dressed ott' when the engraving is done and tho-fiUing set 
by iDrushing with wet whiting and then with a softer 
brush and dry whiting to give the finishing polish. 



32 



Cyclopaedia of Mechanics. 



The Preparation of Kaolin.— Kaolin or China clay Is 
the basis of porcelain and many pottery clays, and is 
produced by the decomposition of felspar. Kaolin oc- 
curring in the position o£ the original lelspar is called 
residual kaolin, and frequently it happens that this is 
carried away by the streams and deposited as sediment 
in a distant locality, when it is known as transported or 
sedimentary kaolin. The residual kaolin is likely to 
contain fragments ot crystalline quartz, mica, and un- 
decomposed spar, with smaller quantities ot other 
minerals ; wliile the transported kaolin is likely to con- 
tain iron oxide, lime caroonate, and other impurities 
intimately diffused with it. The residual kaolin furnishes ■ 
the purer grade, as its impurities may be washed 
out; whilst the impurities in the sedimentary kaolin 
are not of such a nature as to be washed out. The 
common method of mining kaolin in the United 
States is by means of vertical shafts '25 ft. or 30 ft. in 
diameter, lined with pieces of wood, each Sin. by lOin. or 
12 in. by 21 in. The ends are bevelled, so that when the 
pieces are laid end to end around the sides of the ver- 
tical shaft they form a strong wall capable of resisting 
the great pressure from the clay. As the shaft is sunk, 
the. walls are added to by building from below. Some- 
times the clay is mined fi'om open pits, and in a few in- 
stances it has been obtained from underground galleries 
by using heavy timbers, but in most cases the shafts 
lined with wood are found to be the safest and most 
economical method. The ditfei-ent methods of washing the 
kaoli u to I'emove the coarse impurities are allbasedonthe 
same principle, that of flotation. The material Is thrown 
into water, and the particles of the clay, being liner and 
lighter than those of the impurities, remain longer in 
suspension: hence it is only necessary to increase the 
length of the troughs through which it is carried or to 
decrease the x"ate of ilow, or both may be done, to get the 
required degree of fineness in the kaolin, and remove 
practically all the foreign ingredients. One method 




fial 
Setting Out Frame for YTheelbarrow. 



commonly employed is to feed the crude material with a 
current of water into an ordinary log washer! this con- 
sists of a horizontal beam from 10ft. to 25ft. or more in 
length, revolving in a horizontal, rectangular, or semi- 
cylindrical trough of about twice the diameter of the 
beam. Mounted on the beam are numerous short arms 
or knives which cut and stir up the lumps, and at the 
same time carry it slowly to the other end of the trough. 
The current of water carrying the clay passes from the 
log washer into a trough or a zigzag series of troughs. 
The length traversed by the current in the washing 
troughs and the rate of flow may be varied to suit the 
character of the material used and the grade of kaolin 
required. The greater portions ot the coarse sand and the 
larger particles are dropped either in a log washer or 
close to it, and sand wheels are used to remove this and 
prevent the troughs from being clogged. The finer 
sand and the mica flakes are deposited in the zigzag 
troughs, which are usually about 700 ft. long; they a,re 
opened and the deposit is scraped out at intervals. 
The kaolin carried in suspension by the water flowing 
through this long zigzag channel is run into larger vats 
or settling tanks. I'rom these, after a time, the clear 
water is drawn off and the mud is pumped into a filter 
press and squeezed by hydraulic pressure. The presses 
consist of a series ot flat iron or wood frames, strung on 
a central iron pipe. Bags of heavy cloth are placed in 
the spaces between the frames and connected with the 
central pipe, which is connected with the pump. The 
kaolin comes from the filter press in large cakes either 
round or square, and so that they may dry, these are 
exposed in racks to the air for several weeks, or put on a 
floor or in a tunnel and heated by steam or not air. 
The cheaper grades of clays are not put through a filter 
press, being either dried in the settling tanks or 
transferred to a drying floor directly from the tanks. 
Another method of washing is to put the clay with 
water Into vesBels, where it is thoroughly disintegrated 
by means of plungers. It is stirred up into a slip 
which is run off through troughs to settling tanks, 
made preferably of cypress wood. The kaolin slip is 
carried thence into the other tanks, whence it is pumped 
Into the filter presses. The clay is removed from the 
press to the drying floor, heated by exhaust steam. 
To obtain high grade kaolin, such as that used in 
making paper, it Is usually easy to get rid ot grit by 



elutriation and settling In the washing troughs, vats, 
etc., iron being avoided by the proper selection of nia- 
terial.' The chief trouble is often the pi-esenoe of almost 
microscopic plates ot mica, which the washing process 
often fails to eliminate, and which have to be removed 
by passing the wet material through a very fine silk 
mesh. 

Cleaning a Varnished Map.— To remove dirt from a 
varnished map, rub the map with a damp cloth or sponge. 
Most of the dirt can probably be removed by placing the 
map on a table and rubbing stale bread-crumbs over it 
with the palms of the hands. 

Painting Staircase hung with Wallpaper.— The 

course to be adopted in painting a staircase hung with 
wallpaper is as follows. The first thing is to remove 
the paper with water containing a little soda, and to 
rub down the walls afterwards vrtth pumice-stone and 
water. Then fill up with distemper paint, and, when 
dry, rub down with glasspaper. Give two good coats 
of size, one hot and thin, the other chilled, to stop 
suction, make good any defective parts, and again 
glasspaper down. Coat with colour, nearly all oil and 
very thin, and follow with, successive coats of paint 
until a satisfactory appearance is gained. Over dis- 
temper filling the first coat should be oily ; over wood- 
work it should be fiat— that is to say, it shciuld contain 
a oompaTatively large quantity of turps. 

Setting Out Frame lor Wheelharrow.— This is an 

easy method of setting out the frame tor a wheelbarrow. 
Make a drawing of the plan of the framing, as shown 



Fia2 




FiaS 



at Figs. 2 and 3, to a large scale, or full size. IText set a 
bevel to the angle ot the mortises and shoulders as shown 
at Fig. 3. Then the exact length ot cross-bearers or 
rails can be taken direct from the drawing, and the 
shoulders can be set out with the bevel as shown at 
Fig. 1. 

Fainting Concrete Surfaces.— For painting concrete, 
four or five coats of paint should be applied, the first and" 
second coats of white lead well thinned with oil, and the 
later coats mixed with equal quantities of turpentine 
and oU. Every coat must be allowed to dry before the 
next is laid on ; on no account should the concreiie be 
painted before it is quite dry. 

Measuring Land.— In ascertaining the contents of 
land, it is usual in measuring on a sloping surface to make 
allowance for the difference between the sloping length 
and the true horizontal distance, the latter being the 
length for buying or selling and lor plotting on paper. 
There are various instruments and tables for giving this 
allowance, or it may be calculated thus : A fall of 5 ft. 
vertical in a length of 80 ft. on the slope would give a 
horizontal distance of Vao^ - 5' = 79-8ift. A tal l ot 10ft. 
in 180 ft. would give a horizontal distance ot VigO' - V? 
= 179'72ft. Usually, the measurements are taken with a 
chain of 66 ft., and an allowance per chain, according to 
the slope in degrees, is made by pulling the chain tor- 
ward ilink, or whatever the requisite allowance may 
be, beyond the arrow, and then shifting the arrow 
forward. 

Method of using Bnamel.— Patent enamels should 
be used with the same precautions that are adopted in 
the case of any other enamel. Enamelling should be 
done in a warm room. GJet a clean flat ground on the 
work, give one coat ot enamel, and do not retouch it. 
If the first coat is not satisfactory, rub off the gloss, 
or flat it, because enamel should never be put on a glossy 
ground; then give another coat. Enamelling should not 
be done when the weather is damp or foggy. 



Cyclopaedia of Mechanics. 



33 



Polish for Mangle KoUera. — To make a polish 
ror the rollers of mangles and wringers use 1 pt. of 
methylated spirit, 2 oz. of gum sandaraoh, 2 oz. of 
seed lac, 2 oz. of gum benzoin, and 2 oz. of best 
beeswax. Dissolve the wax by gentle heat in sufBcient 
turpentine to make a thin paste, and add It to 'the 
above after the gums are dissolved and carefully 
strained. Mix well together, and apply with soft flannel 
01- a wadding pad as used by polishers. It the mixture 
IB too thin, or seems a long time in giving a good result, 
or IS to be applied by means of a camel-hair brush 
instead of pads, add more seed lac. 

Design for a Small Porch.— The addition of a porch 
roof over the door of a workshop or tool house may 
be made both useful and ornamental. Eigs. 1 and 2 
illustrate a design in which the porch roof is covered 
with imitation tiles cut out of oilcloth. This porch 
roof is suitable for fixing over a door 3 ft. wide. The 
(ramework is made of yellow or red pine, IJin. square, 



passing nails or screws through the vertical posts, the 
root must be placed in situ so as to have an equal overlap 
a,t each end, the loose tiles being temporarily removtd 
for this purpose. The top edge of the root can be neatly 
finished oft by nailing on a strip of wood 1 in. wide, i in. 
thick, bevelled on the front edge, and painted to match 
the tiles. If the upper edge of the roof is in C(?'>staot with 
a brick wall, it is advisable to fiash the joint with sheet 
lead or zinc ; but if the eaves of another roof pass over 
the door this flashing is unnecessary. 

Details of mariner's Compass. — The compass 
bowl is suspended in gimbals in order to allow it to 
retain its horizontal position independently of the 
fship's motion. From the centre of the bottom of the 
bowl is a vertical steel-pointed pillar ; the compass 
needle is fitted with a brass cap, in which is fixed 
an agate bearing that rests on the steel point. The 
compass card is divided on its edges into degrees, the ' 
degree circle occupying about J in. of the card edge ; the 





De8lg:ii for a Small Porch, 






II 

: 31 , 


■ ^f 


kn 


^V 



Fio. 3 



of which 16 ft. will be required ; the various lengths 
being cut oft in accordance with the dimensions 
shown in Pigs. 1 and 2. Only one side of the porch 
Is shown in Fig. 1, the other side being exactly 
uniform. The horizontal piece is mortised into the 
vertical one, and wedged at the back, all the .joints 
beingclosed with paint and secured by nails or screws. 
For Gutting out the tiles, obtain some odd pieces of 
oilcloth of any pattern desired. Cut out of sheet zinc or 
tin atemplate of the pattern and size considered suitable, 
(Fig. 3) , and from this template cut the tiles out of the oil- 
cloth, care being taken to discard all pieces having holes 
in them. "When a sufficient number of oilcloth tiles 
has been prepared— the roof under consideration re- 
quires filty-flve— paint them red on both sides, two 
coats i If only the upper side is painted, the sun and rain 
will cause them to curl up. Then nail them on to some 
thin wood, matchboard being preferable, using tinned 
tackB. Before commencing to nail the tiles down to the 
boards, a slip of wood Jin. thick, Jin. wide, the length of 
the roof, must be fastened along the bottom edge to 
form an eaves plate, as shown at A (Pig. I). Commence 
nailing the tiles on along the bottom edge, driving a 
tack in each top corner. The tacks holding the end 
tiles on each row must not be driven home, as it will be 
necessary to take these off in order to fasten the roof on 
to the framework. It is easier to paint the frame of 
the porch (giving it two coats) before fastening it over 
the door. After securing the framework in position, by 



next circle contains the numerals of degrees marked 
from at the north and south points to 90° at east and 
west. Thus the reading in degrees at sea is taken from 
the south point for the southern semicircle- e.17. what a 
surveyor reads as 120° the helmsman reads S.6()''E. The 

Soints, thirty-two in number, are as follows. North, 
■. by E., N.N.E., N.E. by N., N.E., IT.E. by B., E.N.E., 
B. by K. ; East, E. by S., B.S.E., S.E. by K, S.E., S.E. by 
S., S.S.E^S. by E. ; South, S. by W., S.S.W., S.W. by S., 
S.W., S.W. by W., W.S.Wy W. by S.: West, W. by N., 
W.TS.W., W.W.by W., N.W., N.TV. byis., N.N.W., N. by 
W. These letters are printed radially towards their 
respective positions at lli° apart, which equals 1 point- 
that is, 363° -?- 32. The central portion of the card is de- 
corated with a star to help in distinguishing the points 
at a glance. The card is cemented to the needle and 
adjusted to hang horizontally by dropping sealing-wax 
on the under side where required ; the glass lid screws on 
to the bowl, which is of copper. 

Reducing Paper to Pulp.— Boil the paper with a, 
solution of caustic soda, using some sort of stirring 
or beating arrangement to break up the felted fibres. 
It should then be turned into a tank and washed 
with water until free from alkali. It a flexible 
material is desired, add some soap to the pulp and 
boil, then add alum solution until the soap.7 feel has 
been destroyed; this will produce an alumina soap 
which will bind the fibres. 



34 



Cyclopaedia of Mechanics. 



Chrome Tanning. — A chrome tanning tath is 
made, according to an American Jiatented prooees, 
in tliis manner. Twelve pounds of chromic acid 
are dissolved in gal. oi liydrochlorio acid of a 
speciflo gravity of 1"U6; 50 lb. of chrome alum are 
dissolved in about 20 gal. of water; thirdly, 75 1b. 
of washing soda are dissolved in about 10 gal. of 
water. The soda solution is now slowly poured into the 
chrome alum solution until the result appears cloudy 
and a sparkling silver mist Is seen on the surface, 
wlien water is added to make up the liquid to 44 gal. 
The solution is now run into the chromic acid solu- > 
tion and the whole allowed to settle. A li per cent, 
solution of this liquid is used for the chrome bath (i.e. 
ligal. of the liquid to 98igal. of water) for tanning, 
and the hides are hung in this. As the tanning proceeds, 
the strength or the bath Is made up by more liquor to 
4 or 5 per cent., and the temperature of the bath is kept 
at 80° F. When the thickest parts of the skins show a 
bluish-green colour, the tanning has proceeded far 
enough ; the hides are then washed in water containing 
1 oz. of borax in 20 gal. The time of tanning is for sheep- 
skins about one hourj goat-skins aboiit one and a 
half hours ; calf-skins two to four hours ; and heavier 
materials ten hours. 

Arrangement of Tinmen's Workshop.— A workshop 
of convenient size for four tinmen is shown by the accom- 
panying diagram. The benches B, made of beech-wood, 
should be firmly built, and secured to the iloor by 
Iron brackets. Racks for small tools could be placed 
on the wall at the back of each bench, and the pipes 
from the stoves S carried to the chimney over the forge F. 



add Infusion of 6oz. to 9oz. logwood chips previously 
made, and re-dye at a lower temperature (122" P.). 
Madder might be tried alone ; it is, however, used prin- 
cipally In cotton dyeing, and the operation is a very 
complicated one. For sallron, use a tin mordant 
followed by an infusion of saffron. The latter sub- 
stance is much too expensive to use for commercial 
dyeing. Turmeric in powder must be dissolved in 
methylated spirit, and the solution filtered ; the 
feathers are then dipped in, removed, and dried. 

Preventing Steam Condensing on Shop Windows.— 

The chief cause of steam condensing on shop windows 
is insufBcient ventilation. In constructing shop fronts 
provision should always be made tor an iron ventilating- 
grating at the top of the sash as at A (Fig. 1) ; also toi 
a fanlight over the door as at B (Fig. 2). The grating 
may be fitted with a hinged flap on the inside so that it 
can be closed when not required ; the fanlight is hinged 
to the transom to fail inside on quadrants, or is Jitted 
with gearing. The siU of the sash is prepared for the 




Plan of Tinmen's Workshop. 

Hooks for carrying bundles of wire might be placed on 
the wall behind the rollers. The larger sheets of metal 
could be stood on their long ends in the racks L, M, 
and B, and the smaller plates in boxes on the top of the 
racks. The letter references not already mentioned are 
as follow : A B, angle bender ; A P, ash pan s C P, coke pan j 
H B, hollowing block ; E, rollers ; and T B, tool rack. 

Faint for Mirror Back.— The silvered back of a 
mirror may be protected by applying two coats of a 
mixture of Jib. of red lead ground fine, 2oz. of paper 
varnish, and 4 oz. of turpentine. Allow twenty-four hours 
to elapse before applying the second coat. 

Dyeing Feathers.— Feathers are now dyed almost 
entirely with coal tar or aniline colours, these being 
very brilliant. Although most of them fade, some 
stand exposure to light extremely well. Previous to 
dyeing, all feathers should be soaked in a hot bath 
containing a moderate quantity of Castile soap, 
followed by a second bath of washing soda or car- 
bonate of ammonia-, these remove aU grease and 
soften the feathers so that the dyes penetrate 
better. It is dilBcult to advise with regard to colours; 
experiment with the recipes that are given below. 
Cardinal : Boil I lb. of ground cochineal in 1 gal. of water, 
filter, and, while hot, steep the feathers for one hour; 
remove, add to the bath 2i 11. oz. of tin solution, replace 
the feathers, and keep the bath hot for several hours. 
To prepare the tin solution, dissolve 8oz. of tin in 6oz. of 
hydrochloric acid and 3 oz. of nitric acid. For indigo, 
boil for half an hour in a bath containing 4 oz. alum, 2oz. 
«.r«[ol. and 11 oz. extract of indigo ; run off half the bath, 




Fig 3 Fie. 4 

Preventing Steam Condensing on Shop Windows. 

escape of condensed moisture (see D, Pig. 1) ; the bead 
which fixes the glass will intersect with the bead on 
the Bill in the hollow, and from the outside a hole is 
bored and a zinc tube about | in. diameter is inserted 
(see dotted lines) ; this will carry away any water that 
may collect and prevent it running on to the show- 
board. Pigs. 3 and 4 show, open and closed respectively, 
a glass louvre ventilator for fixing on to the plate-glas» 
in the sash ; these ventilators may be effectually used 
when there is no ventilator at the top of the sash. 

Staining Tonquln Canes.— The hard, crusty surface 
of canes renders them practically impervious to water 
stains. A brown tone may be gained by scorching the 
canes in a gas flame— a gas-stove fiarae for prel:erence. 
Bamboo workers generally colour up the articles after 
they are made. This is done by mixing suitable pig- 
ments, as Vandyke brown, brown umber, or black, with 
French polish or spirit varnish thinned out with 
methylated spirit, a coat of clear varnish being applied 
afterwards for finish. If the canes have been stored 
in a damp iilace to render them soft, try a stain made 
by mixing Vandyke brown with American potash an<J 
hot water. 



Cyclopaedia of Mechanics. 



35 



RenderSns Wood Fireproof. -There have heen a 
great number of compounds or mixtures pi-oposed for 
tlreproottng wood, fabrics, and other iniammable 
materials. Among the beat of these may be mentioned 
ammonium chloride, ammonium phosphate, ammonium 
Bulphate, alum, borax, boric acid, calcium chloride, 
magnesium chloride, sodium silicate, sodium tungstate, 
stannous chloride, and aluminium hydroxide. Any of 
these may be applied in solutions of 5 to 10 per cent, 
strength, except the last ; aluminium hydroxide is 
formed as an insoluble substance in the fibre by 
soaking first in aluminium sulphate solution and after- 
wards in ammonia. Alum is very often used, and by 
some sodium timgstate is considered the best preventive 
of fire. A gooii mixture is ammonium chloride 15 parts, 
bono acid 6 parts, borax 3 parts, and water 100 parts, 
heatedjto boiling, and the wopd or fibre plunged into it. 

Electrical Engineer's Tool Chest,— The accompany- 
ing drawings show the construction of a suitable tool 
chest for an electrical engineer. The sides, lid, and 
bottom should be made of wood about | in. thick when 



The lime should always be freshly burnt, as stale lime 
loses the power of setting firmly. For the very best 
lime mortar, hydraulic lime should be used, stone or 
gi-ey lime being used in cheaper mortars. Hydraulic 
limes should be finely ground, otherwise they are liable 
to slake when thej' have been built in the work, and the 
sjrelling which ensues will crack and spoil the wall in 
which they have been used. Also hydravilic lime mortars 
niust be used immediately they are made, as they set 
rapidly as .compared with the stone or grey lime mor- 
tars. Chalk lime should never be used for building 
purposes, except in smaU sheds where cost prohibits 
the employment of a better lime. Chalk limes must 
not be used In making mortar for dwelling-houses. 
All limes before being mixed with sand should be 
thoroughly slaked. This is generaily done by measuring 
out the required quantities of lime and sand, and 
forming with the sand a ring in which the Ume is placed, 
water being added in suificlent quantities to slake the 
lune, and care being taken not to add more than ie 
necessary. The slaking commences by the lime absorb- 
ing the water, and the swelling of its bulk, accompanied 




Electrical Engineer's Tool Chest. 



ftnished: the trays can be of thinner wood, about 
i in. or j in. finished size. In the isometric view, part of 
the top tra.y is shown cut away, and also the front of the 
box, so as to show more clearly the construction of 
the interior. 

Clock Striking too Quickly.— To prevent the striking 
train of a clock running too fast, it is controlled b.y a 
"fly," which is a small fan fixed to the last^ pinion of 
the train. The fly should be sutBciently tight to turn 
when the pinion turns. If it is loose, the pinion is 
liable to run round quickly while the fly stands still 
and allow the clock to strike too rapidly. Therefore, 
sen that the fly is tight upon its pinion. If it is, 
and the clock still strikes too fast, try extending the 
surface of the fly as much as possible by gumming paper 
to its edges. 

Sliiclng and Preparing Mortars.— Often a wall has 
its strength estimated by the amount of power necessary 
to crush the bricks, instead of by the forces or influences 
that will render the mortar unflt for its purpose. The 
mortar should be made from the very best materials 
that can be obtained, as practically the strength of 
the mortar determines the strength of a brick structure. 



by hissing and giving off of steam ; the purer the lime 
the more violent is the slaking process ; hydraulic limes 
sometimes take hours to commence, whUe chalk Umes 
start immediately. The sand is shorelled over the 
slaking lime, and the whole mass is left for a sufBcient 
time, after which the lime and sand are thoroughly 
incorporated, making the required mortar. The sand 
used must be free froip all earthy material, pit sand 
being considered the best; if the sand does contain 
organic or clayej^ matter, it should be washed before 
use. The proportion of sand and lime used in forming 
mortar are stated on p. 89. 

Recipe for Branding Ink To make a branding ink, 

saturate water with 1 oz. of either gum tragacanth or 
gum arable. Work up bone black into a stiff paste 
with the gum solution, and incorporate with a small 
quantity of soluble Prussian blue or indigo: add a 
few drops of creosote, and press into boxes. Glycerine 
may be used in place of the gum solution, and makes a 
very nice ink, but it does not dry vei-y quickly. Another 
method is thoroughly to work up equal parts of soluble 
Prussian blue and lami)black or bone black with a little 
glycerine. Then make it into a paste of suitable stiffness 
with solution of gam arabio. 



36 



Cyclopaedia of Mechanics. 



Making Upholsterers' Pom-poms.— One way of mak- 
ing the pom-poms u sed by upholsterers is to lap a wood or 
cardboard washer with three or four thicknesses of fibres, 
which may be of silk, worsted, or cotton. Out all 
the fibres at the outer edge of the ring with a pair of 
pointed scissors ; this will release the ring. Bind the 
tuft In the centre with fine silk twist, and trim the 
pom-poms to shape. Another method is to Itnock two 
smooth spikes into a hoard, say 1 ft. apart, wrap the 
materials round the spikes to the required thickness, 
and tie up every li in. Cut off (in the centre of each tie, 
which will make eight pom-poms. Flatten with a blow 
from a mallet or by pressure. Por fine work a rough 
creel could be fitted, and ten to twenty of the strands 
wrapped at once. A vandyked edge could be given to the 
pom-poms by trimming with a mattress tuft punch. 

Iflght Table for Bedroom.— Figs. 1 and 2 are end and 
front views respectively of a light table that might 
stand by the bedside for the convenience of an invalid. 
For the ends, procure four pieces of wood each 2 ft. 6 in. 
long, and planed to IJ in. by J in. These are fixed per- 
manently together In pairs with screws (not shown) . Only 
two connecting bars are required, these being 1 ft. Si in. 
long, planed to 1 In. by ^iu. Fix these to the ends as iu 
Kg. 1. For the foundation of the top obtain a board 
about 2 ft. long, 1 ft. 3 In. wide, and i in. thick, either in one 
piece or by glueing two pieces together. This may be 
covered with oilcloth of the chequered Indian matting 



halt of the mould is made. This method obviates 
making an odd - side. Probably an iron moulding 
machine, similar to those used in wheel moulding, etc., 
would be an assista.iice, as the moulds could be more 
quickly made by using machine pressure. If using the 
above-named machine, the pattern plate, which sei^re» 
as the parting plate, has halt the pattern projecting 
from each side, as previously stated. The mould is 
formed in sand contained In two moulding boxes which 
are placed on the pattern plate, one over and one under. 
The sand is pressed within the moulding boxes by the 
action of rams, which serve also, upon the removal of 
the pattern plate, to eject the sand moulds from the 
boxes. The advantage of the machinejs that mouldb 
may be made iu one-eighth the tim^used in hand 
moulding. 

Preserving Clay Figures.— If the clay figures have 
been painted with ordinary oil paint It would be im- 
possible to fire them, for the heat would immediately 
burn away the,colours. Besides, the heat of an ordinary 
oven would have little effect on the clay except to 
dry it. To preserve modelled objects without casting, 
model them in plaster-of-Paris. A little glue added to 
the water when gauging the plaster will prevent it 
setting, with the result that the plaster may be 
handled like clay. Cream of tartar will also retard 
the setting properties of plaster. When q,uite hard, the 
modelled figure may be dipped in melted paraffin wax, so 





Light Table for BedroonL 



pattern, which Is easily washed, and which may be fixed 
down with thin glue. Fig. 3 shows how the bars on the 
under side are arranged. They are all of 1-in. by J-in. 
material. First glue and screw on those marked A, B, and 
C (Fig. 3), and then by long screws fix those markedB and 
E to the tops of the pieces forming the ends, shown by 
black rectangular patches. Now place the top in 
position and glue securely to the bars D and E, and screw 
from the under side. Eun a piece of stop bead li in. by 
}in. round the top and mitre it at the corners. This 
gives a good finish and prevents anything sliding ofE the 
table. Two co^ts of blue enamel paint may be given 
to the article; or, if made In hardwood, it might be 
polished. 

Stump Moulding, — The term stump moulding is 
generally applied to ironfounding, iu which parts of 
cast-iron are add^d to other castings or to wrought- 
iron work, as in bedstead work, where the cast-iron 
knuckles are cast on the angle-iron forming the side- 
stays. This operation is done In the same way as 
ordinai-y founding, by placing the part to be inserted 
In the finished mould and pouring the metal on It. 
In brassfounding the term denotes the method used 
iu cook-founding known as plate casting. In this 
method the patterns are specially made and fixed on 
a metal plate in a frame, which is reversible. Instead of 
the moulding tub, use brackets on the wall or other 
stand in the shop. The mould is made to one side first 
by applying the peg-side and making the mould in the 
ordinary manner. The peg-side is removed, the plate 
frame is reversed, a, hole-side is put on, and the other 



that it becomes susceptible of a high polish, and by the 
addition of certain pigments to the wax a colour may be 
imparted to the figure. For instance, a little yellow 
ochre will give the appearance of old ivory. Drapery 
may be represented by dipping strips of cloth in the 
plaster and arranging them on the figure. To judge the 
afnount of size water to be used when gauging the plaster, 
dissolve some good glue in water aud measure a certain : 
quantity of this with a certain quantity of water. With 
the mixture gauge a small quantity of plaster to dis- 
cover how long the mixture takes to set. Small clay 
models, if varnished, may be preserved for an indefinite 
time, but, being simply dry clay and not having been 
burnt, they are easily broken. 

Colouring Gold Articles. — Gold alloys of not 
less quality than 15 carat may be made to assume 
the colour of fine gold by carefully boiling them 
in a mixture of nitrate of potash 16 oz., table salt 
7oz., alum 7oz., and spirit of salts loz. The work 
must be previously annealed aud boiled out in aqua^ 
lortis pickle, and wired with platinum wire. It niust 
only be exposed to the colouring mixture for five 
minutes at a time, and well rinsed in boiling water 
between each operation. If 18-oarat gold alloys are 
employed, the colouring mixture may consist of 1 oz. 
more of each of the above ingredients, omitting entirely 
the spirit of salts, and making the other powders into a 
paste with hot water. In all cases it is advisable to thin 
the colouring mixture with hot water as the process 
of colouring progresses, so as to avoid overdoing the 
work. 



Cyclopaedia of Mechanics. 



37 



Making Red Stencil Ink.— Below are instructions 
on makiug a red stencil ink for marking boxes, etc. 
Get 3 lb. of pure pipeclay (not a mixture of pipeclay 
and whiting), and crush or scrape into a fine powder. 
Make a stiff mixture of Indian red in water, scrape 
a few shreds of soap into the Indian red, and mix well. 
Now gradually add the pipeclay until the mixture is 
of the consistency of putty. Then make it into cakes, 
and dry with gentle heat for use. 

Determining Diameter and Fitch of Rivets.— 

For single riveting up to 1-in. plates the diameter of 
the rivet may equal one and one-fitth times the square 
root of the thickness of the plate, the rivet hole being 
one-twelfth larger. The pitch may equal I'O!) in. plus the 
diameter of the rivet hole. Tor a }-in. plate the rivet 
by this rule would be 1<^ in. in diameter and the pitch 
about 24 in. 

Baker's Steam-beated Owen. — The accompanying 
sketch shows the piinciple ot improved decker ovens, 
heated by steam, tor baking bread. It should not be 
taken as a working drawing, as the erection of such 
ovens must not be undei'taken without previous ex- 
perience, or working to a, maker's particulars. The 
ovens are heated by a row of tubes running from back 
to front, the back ends starting from the furnace flue 
as shown, whence they slope' upwards. The tubes 
are each separate and have their ends welded up, but 
preyious to being closed they are about one-flfth filled 




Baker's Steam-heated Oven. 



with water. The sloping position of the tubes causes 
the water to come where the heat is felt, with the result 
tha;t the tubes get quickly filled with high-temperature 
steam. It will be noticed that the furnace comes at 
the rear of what may be considered the front of the 
ovens, and all stoking is done away from where the 
preparation and baking are done. 

Chinese Lacquer Work.— The red gold and pale 
yellow effects seen on Chinese lacquered cabinets, etc., 
are produced by the aid of lead, tin, or silver foil laid 
upon a smooth surface, and coated with various gum 
Tarnishes. Very effective panels may be made upon 
this principle, and these may be utilised in the con- 
struction of screens, cabinets, etc. When sheet metal 
is used it should be perfectly free from marks of any 
kind, and should be highly polished. If wood is em- 
ployed it must be planed very flat and then smoothed 
with fine glasspaper, being afterwards sized and primed 
with two coats of white lead and yellow ochre mixed 
with drying oil and a little oil size ; rub down each coat 
with pumice powder and water. Next coat with flat black 
and rub down, first with finest sandpaper, then with a 
dry cloth, and finally with the palm of the hand, taking 
preat care that particles of dust do not remain. Now 
give an even coat of a mixture of 2 parts of black japan 
and 1 part ot gold size, and after rubbing down, 
when dry, with pumice powder and water the panel is 
ready for the silver leaf. The portions to be treated with 
foil are then coated with gold size to which has been added 
a small proportion of linseed oil, and when these parts are 
of the proper "tackiness" the leaf or foil is laid on, as 
in gilding. When dry and the surplus metal removed, the 
subjects are toned, shaded, and tinted ; for the darker 
shades, di agon's blood mixed with turpentine is used ; 
gamboge lorms the lighter shades. All the transparent oU- 
colours, as used by artists, may also be used for various 



effects upon the foil. In say a landscape, the figures, 
sun, and water may be covered with loll, whilst the 
other portions ot the landscape may be executed in oils, 
and should be suggestive rather than detailed. When 
dry, wash with water ocntaiuiug a very little soda, and 
finish by varnishing. 

Making Wrought-iron Cone.— Below is explained 
how to make from J-in. thick plates a wrought-iron 
cone of a rather pronounced slant. The lath being so 

freat, the flange may be thrown oH, and the seating at 
he small end of the cone worked in after the cone has 
been bent to shape and the seams made. To cut the 
pattern for a cone made in this manner, first draw an 
elevation of a section through the centre as A B C D. 
Produce the sides of the cone, and make the length 
to A' B' equal to the length necessary for the flange, 
and also make the length to 0' ebual to the length to be 
worked in to form the seating. Where the lines produced 
intersect at O is the apex of the cone. Use this as 
centre, and with the radius O A' draw an arc of a circle. 
Now djvide the quarter circle 0' B' E (using 0' B' as radius) 
into any convenient number of equal parts, and set off 
a corresponding number of similar divisions on the 
curve of the pattern, as A' 1. Now take the distance A' I 




Pattern for Wrought-iron Cone. 

and set off from 1 to give the point 2; if a line were 
drawn from 2 to the centre O this would give one-half of 
the pattern. If it is found convenient to cut the pattern 
in one piece, set off two other divisions as 3, 4. Join -t 
to the centre O, and then with O as centre and O 0' as 
radius, describe the arc of a circle shown to form the 
small end of the cone. The cone could be partly bent 
to shape in the roUei's, and then worked round true 
upon a mandrel. Braze the seams, and then throw off 
the flange with a stretching hammer, working it to an are 
of a cil"cle first upon the mandrel, and then working it 
down flat afterwards upon the flat end of the anvil. The 
small end could be set in by woming overhand upon an 
upright circular stake with the edge bevelled off. First 
tuck the metal in round the edge- with cross blows from 
the stretching hammer, then set it in on the shoulder of 
the head a short distance down from the part first tucked 
in. Now work from this furrow up to the top edge, beat- 
ing the metal over while working upwards to form the 
shape required. Again tuck the metal in at the top, and 
repeat the process described above until the work is 
brought to the desired shape. 

Re-blackening Thermometer Scales.— The best way 
of re-blackening the impressed figures and divisions of 
thermometer scales on boxwood is to use a drawing pen 
filled with japan black ; this would of course be a rather 
tedious operation. Another method, but not so good, is 
to paint the boxwood scale all over with japan black, 
making sure that it enters all the lines and figures ; 
then roll up a piece of smooth cloth into a ball, damp 
it with turpentine, and with this remove from the 
boxwood all the japan black with the exception of that 
in the depressions. This should not be difficult If the 
rubber is used gently and the impressions are deep. 



38 



Cyclopaedia of Mechanics. 



How to Clean Engravings.— The following method 
of cleaning engraTinga has heen found eft'eotive when- 
ever dirt and faint stains were to be removed, though 
probably it is not so elBoient as the chloride of lime 
process (described on p. 206) in dealing with stains of 
long standing. The specimen to he cleaned should, 
It possible, first be detached from its mount. Lay 
it face upwards on a clean, Smooth board In the 
sink, or similar place, and sprinkle it with ordinary salt 
till thinly covered^ Then take a lemon, cut it, and 
squeeze the juice over the engraving so as to dissolve 
the greater proportion of the salt. Then raise one end of 
the board to slant at an angle of about 25% and flood it 
with nearly boUing water until all the salt and lemon 
juice are washed away. Drying must he allowed to pro- 
ceed spontaneously. 

Transferring Design to a Saucer.— If it is wished 
merely to fit the design to the concave face of the saucer, 
to be painted over by hand afterwards, fold up the 
drawing which it is desired to transfer as shown 
at Fig. 1 in such a manner as to fit the curved surface. 



colours composing the design there is a certain amounl. 
of oil, which stains the biscuit ware ; this oil has to be 
burned o£C before the glaze is applied. This is done by 
placing the ware in a heated kiln. When the oily uiatter 
has been expelled, the saucer is dipped Into the liouid 
glaze, which is a solution of borax glass containing lead 
salts and silica. The saucer will be dry in about flve 
minutes, when it looks as if It had been whitewashed, 
the design being completely obliterated. The saucer is 
now put in an earthenware sagger, or crucible, and 
heated to a white heat for sixteen hours in the kilu, 
during which period the glaze has fused and turned Into 
a transparent glass through which the design is visible. 
The saucer is now finished. 

Polishing Ebony Mirror Frame.— Unless the ebony 
is of a particularly good quality there will be a brown 
or greenish tinge that should be overcome by wiping 
the frame with a good quality ebony stain, which 
can be bought re^dy made. The frame may then be 
finished by polishing with white or transparent polish. 
Or a combined ebony stain and polish mav be used. 







P^P F,c.3, 



FlCu,2 



and adapt the drawing to these folds. Fig. 2 shows 
the drawing arranged to suit the folds. Manufac- 
turers, however, adopt a different method. Fig. 3 
shows the pattern repeated three times round the 
circle. It will be noticed that the design does not 
entirely fill the circle, but that a small olank space 
has been left. In the necessary folding of the draw- 
ing to fit a circular concave surface the diameter of 
the circle on which the design is drawn must be con- 
siderably larger than that ut the saucer— that is to say, 
in a saucer of 6-in. diameter. It will be necessary to draw 
the design on, say, a 7J-in. circle. The spaces marked 
+ + + in Pig. 3 are left vacant, so that there may be as 
little distortion as possible when transferring the printed 
pattern on to the saucer. Fig. i shows the appearance of 
the paper containing the design when stuck on the 
saucer. The following is the process employed in pro- 
ducing these designs. When a design has been drawn, 
the engraver outs it out on a copper plate, making the 
incisions deeper where' a darker shade is required. On 
to this engraved plate paint is rubbed to fill the lines, 
all superfluous colour being carefully cleaned off. A 
i-heet of thin tissue paper is laid over the plate and 
jiressed into it by means of an iron roller covered by 
three or four wrappings of felt. The print is then cut 
out with scissors, laid round the saucer, and worked into 
place with a dabber made of rolled flannel. The transfer 
18 left on the saucer, which is in the " biscuit," or half- 
fired, state, for half an hour or so, when the paper is 
washed off, leaving the design on the saucer. In the 



This is made by mixing with the polish sufBolent gas 
black or Frankfort black to gain the tone desired. An 
aniline spirit dye is used in most good shops, for the 
reason that it does not thicken the polish. In any case 
the best results are gained if the black i's used thinly In 
the preliminary stages, and the final bodying up and 
finishing out are done with transparent polish. As ebony 
is ^a close-grained wood, no grain filler is required, and 
only a small quantity of polish. To apply the polish 
use wadding pads, slightly moistened with Unseed oil. 

Bemovlug Varnish from Oak Carving.— To remove 
varnish from an oak cai-ving a solution made as follows 1b 
used. Put equal parts of turpentine and methylated spirit 
into a stone jar and place the latter in a saucepan partly 
filled with water— glue-pot fashion. Put this in an oven 
and bring up to blood heat ; then brush the solution ovei 
the carvings. As the varnish softens take it off with a nail 
brush. When all the varnish has been removed, apply 
several applications of oxalic acid- 2oz. to 1 pt. of water. 
SwUl off with plenty of clean water, and finally bruM 
over with common malt vinegar to kill any trace of acid. 

Faint for Leather Trunlis.— To paint leather black, 
first coat it with a solution of alum 1 oz., and water 
Ipt. The next coat should consist of drop black lib., 
ground in turps, and terebine Joz. Thin with turps, 
when this is dry give a final coat of drop black and 
Coburg varnish, mixed to the consistency of cream. 
For white paint use zinc white Instead of black, and 
sugar of lead, ground fine, instead of terebine. 



Cyclopsedia of Mechanics. 



39 



How to Fix MCarqtueterie Transfers.— Marqueterie 
transfers as used by French polishers tor decorating 
furnitiire are fixed as described beiow. The design, 
with a fair margin of paper aror.nd it, is cut from 
the sheet, and is laid, face upwards, on a sheet of 
newspaper. A thin, even coat of good quality spirit 
varnish is then applied with a camel-hair brush and 
allowed to stand tor a tew seconds till the varnish 
becomes stioky. The design is then laid in the desired 
position, face downwards, and pressed well down so that 
all parts thoroughly adhere. After an interval of five 
minutes the back of the paper is damped with warm 
water and pressed down again. The paper, is then 
saturated with water and allowed to stand for a few 
minutes, after which the paper should glide off, all 
surplus moisture being taken up with a clean moist 
washleather. The work is then set aside in a warm 
place. The best results are gained if the design is fixed 
after the work is merely bodied up. The subsequent 
bodying up and finishing will enable a fair body of polish 
to be applied, thus gaining solidity and appearance of 
inlay. To ensure accurate fixing of the design, tally 
marks should be made at its chief points, corresponding 
marks being made on the article to be decorated. 

Crucible Steel Furnace.— The sketch herewith gives 
a sectional view of a crucible steel furnace. The melting 
chamber A should be 3 ft. high from the grate bars B; 
oval in shape, 26 in. by 19 in., and lined with 6-in. 



li'Vin. in diameter; mark off twelve equal parts on the 
edge, and from these draw tangents to the guide circle. 
With a shai'p chisel mark in the lines to about iin. 
back from the jim, and mark lines across the rim join- 
ing the marking on both sides. Saw these lines in about 
iin. with a sharp hack-saw, for j-ecelving the cups. 
From i^-lu. sheet brass stamp the cups with the punch 
(Fig. 3) and trim off with shears. Then place the cups 
in position, tin the joints with a soldering bolt, and 
place the cup disc on a fire to sweat. Castings for the 
bearings should be turned to dimensions (see Fig. 1), 




-J , * ' U 



^'r,if I'll,'" 

Crucible Steel Fdrnaoe. 



canister. The flue E leads from the melting chamber A 
> into the chimney stack F. The cold-air fiue M leading 
from the cellar D is used to regulate the draught. The 
chimney stack P, lined with firebrick, should be from 
35 ft. to 40ft. high. Kisthe cover of the melting chamber; 
I the shelves for drying crucibles ; N the chamber behind 
the stack for drying crucibles, storing charcoal, etc. ; 
and Z, Z the annealing ovens. 

Recipe for Saddle Soap.— To make saddle soap, 

fently neat over a slow fire, constantly triturating till 
horoughly incoi-porated, lib. of beeswax, 8oz. of soft 
soap, 2oz. of linseed oil, and 4 pint of oil of turpentine ; 
put in pots or tins. Kub a' very little well into the saddle 
and polish with a soft brush. 

Small-power Water Motor. — The i motor shown 
in plan by Fig. 1 and in elevation by Fig. 2 will 
develop J^ brake-horse-power with a fall of 30 ft. 
through a 2-in. pipe, and i brake-horse-power with 
a fall of 50ft., the speeds being about 3,000 and 5,000 
revolutions per minute. To make the wheel, get a brass 
casting A (Fig, 1) to be turned to 2|in. diam. by iin. 
wide. Fix centres in the disc and scribe a guide circle 



Small-power Water Motor 

making the groove in the centre an exact fit for the 
A-in. sheet metal, of which the casing is constructed. 
Obtain a casting for the gland to whinh the nozzle is 
fitted, and turn this inside an exact fit for the nozzle. 
From i-ln. sheet iron cut out and bore the two flanges 
(Fig. 1). The lower half of the casing is worked from 
A-in. sheet iron (blued) . First cut out two pieces to shape 
B (Fig. 2) . At each top edge file out a central semicircle 
exactly the diameter for the bushes. From the same 
metal cut two stripe l^jin. broad and 6 in. long, and bend 
them to shape D (Fig. 2).' Fix the whole of these parts by 
twisting thin wire round them and solder all together. 
The top cover is next made in the same way. The nozzle 
gland la then carefully fitted and soldered or brazed 
on. As a caution, do not make the nozzle of a high-speed 
motor more than i-in. bore at the opening, but make it 
larger for a slower speed. 



40 



Cyclopaedia of Mechanics. 



Press for Mangle Shafts.— The accompanying dru.w- 
Ings show, with scale, a machine for pressing shafts in 
mangle rollers to be driven by steam. Two belts, one 
open and the other crossed, drive the pulleys P, L, I", and 
L', and by means of the striking gears P and Q the pinion 
A can be made to revolve in either direction, orthe straps 
can be moved to the loose pulleys. As will be seen, the 
pinion drives the tooth wheel B, and the latter, being 
Keyed on the same shaft as the pinion C, the tooth wheel 
D is driven in either direction as rectuired. D has a thread 
cut in its boss and works the screw E, causing it to move 
backwards or forwards through the thrust block X. The 
plain parts of the screw shaft at F and G are for the pur- 
pose of preventing accident in the event of the striking 
gear not being moved quickly enough. Thus, when the 
tooth wheel D gets on the plain parts it will simply 
revolve without causing any movement of the screw; 
then the screw can be turned into the thread of D by the 
hand wheel H. It will only be at si;ch times as these 
that the screw shaft will revolve, as the hand wheel H 
will be locked to the driving head K as indicated. 
The driving head K works between the planed sides M 
and N. The fixed head at O is simply for holding the 
mangle shaft S in position and tor adjusting the 
mangle roller Z; this latter is held in position by 
means of the four cramps 1, 2, 3, and 4 as shown. The 



on the rubber at tnis stage. When a fair body has been 
obtained on oneside, turn the coffin over and do the other, 
working the head and foot as well. "When the second 
side has about as much polish as the first, turn back to 
the first side, and with veiy fine worn giasspaper remove 
any small lumps. If the filling is well done the grain 
hardly ever rises, except on damp or coarse-grained stuff j 
therefoi'e the old plan of papering half the polish off to 
get the grain down , is avoided by this method. Now 
Quite body up a side— that is, as well as time and price 
will ajlow— and then finish it off, if the atmosphere i» 
reasonably warm, with a few coats of very thin glaze. 
When this side is done satisfaotorily.'treat the other In 
the same manner, finishing the endswlth the second side. 
The lid must be well bodied in and its mouldings glazed 
off, but the top should be spirited out. When agoodibody 
has been applied, wet the rubber with half polish, a 
sprinkling of spirit, and a little oil so that it works 
freely j continue to reduce the polish and oil, and in- 
crease the spirit, until a fair shine is obtained with the 
rubber marks showing in oil. Sprinkle a few drops of 
spirit on a rubber that has not been used for polish, and 
lay two or three thicknesses of clean rag over the face; 
rub this on the work until dry, then wet it again and 
repeat the process ; after three or four such rubbers the 
surface should be w«ll cleaned off and should shine well. 





®8 



. 963? 

Iii li ilillill - 



4 feet. 



Press for Mangle Sha ts. 




Lr=y 



backthrust block E, with its slides T, T, can be moved 
backwards or forwards by means of the hand wheel 
w and screw working through the block V, and when 
adjusted can be firmly held to the bed by the two 
bolts and nuts shown at 5 and 6. The bed should 
be bolted to iron supports or other suitable foundation 
by bolts and nuts shown at 7, 8, 9, 10, 11, and 12. 

How to Polish a Coffin.— The following is a good 
method of polishing a coffin. Coat with linseed oU, 
and fill in with a paste of best Paris white (not 
piaster-of-Paris) and turpentine, coloured with yellow 
ochre for pitch-pine and oak, and with a mixture of 
brown umber and ochre for elm. A very small quantity 
of polish is mixed with this to assist it in setting. 
Eub the filling well in across the grain with a piece 
of coarse rag or a wisp of long tow, and then rub off all 
superfluous filler and leave it smooth and clean. The 
whole body of the coffin, including the lid, should be so 
treated, and should then be allowed to stand as long as is 
convenient— the longer the better. Another good filler is 
piaster-of-Paris, oil, and polish, but it is not so easUy 
used, as it sets quickly ; with this filler do only a very 
little at a time, or it will set and get muddy before 
it can be rubbed off. The polishing may be commenced 
as soon as the work is all filled in ; start with the side 
first filled in. Make a big rubber of wadding, wet it 
well with polish, and cover with a piece of rag ; put a 
little oil on with the finger and lay the polish on with 
long, straight strokes, not attempting to work it, .but 
taking care not to leave any wet streaks. After two or 
three rubbers of polish have been applied begin to work 
It, but unless the coffin is panejled clo not try circular 
work, but use sweeping strokes 3 ft. or 4 ft. long with a 
Bort of twist at each end ; do not scrub backward and 
forward over the same spot. Do not be afraid to use oil 



If time presses, wipe over with a folded rag on which spirit 
has been sprinkled to clear the grease off more quickly, 
but, of course, not so well as by thoroughly spiriting out. 
If too cold to glaze, the body of the wood must be spirited 
out similarly, but the glaze saves time if it can be 
used. Always use a large rubber— one with a face as 
large as the palm of the hand— and do not let it get 
sodden ; but, if necessary, pull it to pieces and tighten 
it up. For a panelled coffin, the above plan must be 
modified a little ; a smaller rubber must be used, and 
•great care must be taken to get into all the corners ; the 
glaze finish is suitable for this also. Note the time spent 
on different portions of the work ; a fair division would ' 
be to allow about two-thirds of time to the body and one- 
third, or rather more, to tlie lid, and take care that about 
equal time is given to both sides, as upon this a satis- 
factory result will obviously depend. First decide how 
much time may be allowed for the job, and then divide 
it up carefully and stick to it, or one part may look tar 
better than another, a result certainly to be avoided. 

Renovating Fur Necklet. — The only practicable 
method of renovating a fur necklet that is moth-eaten 
in parts is to cut away the latter. Open the necklet, 
remove the padding or lining, and place the skin, fur 
side down, upon a table. Cut out the spoilt part with 
a sharp knife on the skin side, taking care to cut only 
through the skin and not the fur below. Now out to 
the required size a piece of skin of the same kind as that 
just removed, place it in position, and sew it in, being 
careful not to catch in the fur. If a spare piece of the 
skiu is not to hand, sufficient must be cut from one end 
of the necklet, thus shortening it. A third alternative 
is to make the necklet of a diflerent shape, neatly join 
ing the small pieces cut off ; probably there will then b* 
sufficient to replace the apoilt parts. 



Cyclopaedia of Mechanics. 



41 



Renovating Silvered Glass.- To renovate a glass In 
one cornel- of which the silvering has assumed a ifrosted 
appearance, or has baoome spotted by damp, proc'eed iu 
this manner. Cut out the aft'eoted silvering, first mark- 
ing it off squarely with a straightedge and chisel; lay 
the glass fiat on its face and apply either of the silvering 
solutions given on p. 103. Mix equal parts of (o) aind (b), 
and pour upon the clear glass, allowing the solution to 
flow evenly over the hare place. Distilled water should be 
used, and the solutions should be kept in black bottles. 

Soluble Prussian Blue used In Inks.— In many ink 
recipes soluble Prussian blue, which is a preparation 
of Prussian blue and ferrocyauide of potassium, ia 
mentioned. This soluble blue is made thus. With a 
pestJe and mortar thoroughly incorporate a quantity 
of ordinary Prussian blue with half its quantity of 
ferroeyanide of potassium. The mixture is then put 
into distilled water and thoroughly shaken from time 
to time ; then it is allowed to stand and the sediment 
filtered off. 

Folding Stand for Baby's Cradle.— Figs. 1 and 2 are 

end and side views respectively of s. folding stand for a 
baby's cradle. To make the stand, procure four pieces 
of sound pine, ash, or oak, as preferred, 2 ft. 7 in. long, 
and plane them to 14 m. by Hn. These form the ends: set 
them out as shown at Fig. 3. Four pieces 1 ft. 11 in. long 



worked now as they were 2,000 years ago. The Abruker 
mine has been sunk about 200ft., following the pitch of 
the vein, and all the mica and refuse are raised and 
carried away by natives. No machinery of any kind is 
used; drills and hammers are the only tools employed. 
The refuse and the mica are placed in baskets which each 
hold about 10 lb., and which are passed up from hand to 
hand by women who stand in aline on a ladder. When th& 
top is reached the baskets are dumped and returned down 
the ladder in the same manner, but by another line of 
women. The crude mica is first roughly trimmed and 
then sorted into different grades, according to sizes and 
qualities. It is then split up, and the size to which it is 
to be sheared is marked upon it. After shearing, the mica. 
is cleaned, weighed, and packed ready for transport. At 
the Abruker mine the packages of mica are loaded into 
carts drawn by bullocks, and carried in this way to sea- 
ports hundreds of miles away ; the bullocks travel at'the 
rate of about ten miles a day. There are many kinds of 
mica, prominent among which are Muscovite, the- 
common potash mica ; paragonite, an analogous soda 
variety t biotite, a magnesia mica having a black or dark 
green colour ; phlogoplte, a bronze-coloured mica found 
in crystalline limestone and serpentine rocks ; lepidome- 
lane, a black mica containing much iron ; and lepidolite, 
the red-rose or lilac lithia ;mica. Mica has many uses. Its- 
chief perhaps being in the electrical industry. The fact 
that mica Is elastic and fireproof, and that Its insulating: 




FiQ 3, 

Folding Stand for Baby's Cradle. 



n.nd planed to 1 in. by i in. will now be required for the 
connecting bars, the ends of which are seen In Fig. 1. 
The two pieces forming each end are pivoted together 
by a brass bolt 2i in. long, with wing nut ; the bars are 
fixed by light screws liin. long. To make the bars on 
which the cradle rests, heat one end of a piece of i-in. 
bar iron and form a ring on a stout screw eye. Bend the 
other end at right angles to fit into a corresponding eye, 
as seen In Fl". 1. when these bars are attached the 
stand is complete. 

Red Oil nsed in French FoUshlng.— In making the 
red oil used in French polishing, the alkanet root is 
merely broJ^en into small pieces and the oil poured over. 
If well stirred up a reddish tinge will at once be im- 
parted i leaving the root In the oil overnight will yield 
a stronger red. The red oil is usually kept in a large 
jar, more oil or root being added as required. The 
addition of a little turpentine assists In fetching out 
the colour If the root is very dry. 

Mica and its Uses.— Mica is an anhydrous silicate of 
calcium and aluminium, and crystallises in a laminated 
mass, easUy split along its axis ; it can be subdivided down 
to n^sK in. In thickness. Deposits of this material are 
found iu various parts of the world. The occurrences of 
pockets In which mica is found cannot be predicted by 
the geological formation of the locality. The best 

Duality mica Is obtained from India, whence has been 
urnlshed the bulk of the world's supply for centuries. 
These mines, the principal of which is the Abrulier mine, 
are In the interior of the country, remote from civilisa- 
tion, and extremely inaccessible. Here the deposits are 



qualities are unaffected by time, has made it peculiarly 
adapted for use with electrical machinery. It has been 
used for vibrating plates In the photophone, and tor 
diaphragms in telephone construction. In commutator 
work mica is almost indispensable, as also is tlie case- 
In hundreds of othei" electrical machines and instru- 
ments. For the purpose of armature Insulation in 
high-tension alternating machines mica is especially 
adapted : unfortunately the expense of the mineral has 
to a great extent prohibited its use. Mica waste has one- 
or two electrical uses. Insulators are made by splitting 
up the mica into laminae and solidifying these thin 
sheets at a high temperature- and under a heavy 
pressure. It is claimed that this treatment increases 
the insulating properties of the mica. Mica replaces 
glass in positions exposed to much heat, is used iu wall- 
paper varnish, and in packings for machinery ; it has 
many other applications. 

Making Glass Beads.— In making small glass beads, 
a portion of melted glass, coloured or uncoloured, is 
taken from the crucible upon the end of a long iron 
blowpipe ; the melted glass is then blown into a thick 
bulb, to which another iron is attached exactly opposite 
to the first. The bulb Is drawn out into a long narrow 
tube by two men, who pull the two pipes asunder. The 
narrow tube, many feet in length, is laid upon supporcs. 
The tube Is cut into very short lengths to form the 
beads. If the beads are to be rounded they are either 
heated In an iron vessel kept In constant motion to 
prevent the beads adhering to. each other while the 
edges just fuse, or they are revolved in a vessel wltlv 
water, when the edges are rounded by mutual at^r.tioii. 



42 



Cyclopaedia of Mechanics. 



Blackening of Silver Goods by Gas.— The coal gag 
us3d for lighting will sometimes cause silver and plated 
guods kept near the gas burners to become discoloured. 
This blackening U caused by the presence of sulphur- 
etted hydrogen in the gas. No special form of burner 
will prevent the blackening of the silver If the gas is 
impure, though the use of an Incandescent burner will 
lessen the evil, because a smaller quantity of gas will be 
consumed. If ttie sulphuretted hydrogen cannot be 
removed from the gas before it is sent out from the gas- 
works, a small puritler filled with slaked lime, through 
whicli the gas must be passed, should be fixed on the 
premises. This lime would remove the sulphuretted 
hydrogen. The spent lime should be removed from 
time to time, and fresh lime put in its place. 

Brass Money Box.— To make a brass savings bank or 
money box (Fig. 1), cut a piece of sheet brass Hi in. long 
by 41n. wide. (Jlean it with emei-y-cloth, planish, bend it 
round over a mandrel, and braze the ends together, using 
borax as a flux. Pile the .ioint smopth, and raise two 
Bwagings on it, each to be 14 in. distant from the ends. 
This constitutes the body. For the foot, cut a disc of 
brass 5i in. in diameter, and hollow it on a block so that 
It resembles an inverted saucer. S*age this about i in. 
distant from its edges, and cut a 2-in. hole out of the 
centre. Now file the edges perfectly plane, and solder 
th2 body on, having first fixed it in the centre. The top 




bronze and then over the parts of the frieze that are 
in reltet. A white coat brushed over with knotting 
thinned with methylated spirit gives a good imitation 
of old ivory. 

Using Watchmaker's Turns for Drilling a Staff, 

etc.— iselow is described how to drill watch stafra 
for fine pivoting. The centres sold with a new pair 
of turns are of Tery limited use, so, when uuying, 
a length of brass rod and a length of steel rod 
to fit them should also be purchased. Prom these 
rods proper runners for turning and pivoting balance 
staffs, etc., are made. The brass and the steel rods 
should be cut up into 3-in. pieces, each piece to form a 
runner. One steel runner, to be used as a back centre, 
should be filed up as at A (Pig. 1), and a minute centre 
marked upon it with a fine centre punch. This is for 
general use in turning staffs and pinions. The other 
end of the runner may have a hole drUled near its edge, 
and a brass pin B (Fig. 1) inserted in the hole ; a small hole, 
through which a pivot can be passed, must be drilled 
through the thin end of the pin. This is a safety back 
centre to be used in turning a'staft, cylinder, or pinion 
that has a fine pivot, which might break if its end rested 
in the centre A ; by passing the pivot through the hole in 
B the strain of turning is taken by the shoulder of the 
pivot only. A steel runner should have fine centre punch 
dots round the end C (Fig. 2), as at E, and be filed 
to a triangle D at the other end, and have three 
centre dots as near the edge as possible as at E. These 
are for front turning centres for pivoting. The tri- 
angular end D is to be used for a Tery fine pivot, thus 
enabling the graver to get at the extreme end of the 



F.ar 
Brass Money Box, 

is made by ciittiug two discs of brass each 5J in. in 
diameter, and hollowing them together on a block, to 
resemble a shallow bovvl. Pile the edges of these per- 
fectly plane, and swage one about iin. distant from the 
«dge, afterwards jennying up a small edge. In this, 
the top hollow, cut a central slot to allow a large 
coin to pass through easily. Now file the bottom hollow, 
so that when an edge has been .iennyed up it will fit 
tightly into the top. Cut a 3-in. hole out of the centre, 
and solder both hollows together, afterwards fixing the 
top over the centre of the body and soldering round. A 
-small slot plate (Pig. 2) will show to better advantage if 
made of German silver. Pile it so that any coin can 
pass through easily, hollow it slightly to fit the top, and ' 
after fixing it in the centre solder it on.- Now, if desir- 
able, cut a name-plate A (Pig. 1) of German silver, and 
stamp or etch the name on ; then fit it to the body, and 
solder it on. Cut a disc of brass about Sin. in diameter, 
t'o be soldered underneath the foot over the 2-ln. hole. 
When full, the bank can be emptied by unsoldering 
this disc, without in any way injuring the bank. • Scrape 
off superfluous solder, and clean with emery and oil. 

How to Bronze a Frieze.— Here are instructions on 
Bronzing a Cordelova (imitation plaster) frieze. Apply 
to the frieze two coats of oil paint. For the bronze 
■colour, mix in oil J lb. of burnt umber, J lb. of Brunswick 
green, and add Venetian red until a ^ood bronze colour is 
obtained. A penny that has been in circulation for a 
year or two may be used as a colour test. Thin the 
colour with half varnish and halt boiled oil, and give 
the frieze a good coat. On the following day, while the 
f lieze is still tacky, apply bronze powder (copper, silver, 
or gold) to the parts of the frieze in relief. A paper- 
hanger's roller covered with plush can be used for this 
i)urpose. Kun the pludh-covored roller through the 



Method of Drilling Watch Staff. 



pivot. A brass runner should be filed at both ends, as 
shown in Pig. 3, small holes of graduated sizes being 
drilled through its end, through which pivots can be 
passed to round up and burnish their ends. Another 
brass runner should be filed at each end, as shown in 
Pig. i, slight grooves in which pivots can lie during 
polishing with oilstone dust and red-stuff being made at 
the ends ; one end should be kept for oilstone dust and 
the other end for red stuff. Por drilling staffs and 
pinions, a central hole must be drilled in a brass runnel 
and a short drill made and inserted friction-tight. The 
back pivot of the staff or pinion runs in a brass safety 
centre like B (Pig. 1), but in the centre of a runner. The 
work is revolved by a bow against the drill, which is held 
to it by the right hand, and slowly revolved to keep it 
true. Before drilling, the broken plTOt is filed off flat, 
the centre carefully marked by a pointed chamfering 
tool, and care is taken that the drill is started in this 
centre. Pig. 5 shows a pinion being drilled with the 
parts in position. Pig. 6 shows a pivot being turned on 
a staff. Fig. 7 shows a pivot being rounded up with a flle. 
Pig. 8 shows a pivot being polished by a steel polisher. 
In all these illustrations the DOW and ferrule are omitted 
for the sake of clearness. 

The Use of Fusible Plugs.— A fusible plug is a brass 
case containing a core of an alloy that will melt at a 
temperature a little higher than the heat of the water or 
steam in the boiler. It is practically impossible for the 
core to refuse to melt if the boiler runs suHiclently 
short of water to leave the plug exposed to the fire heat 
only, though, owing to ignorance, the plug might be 
placed where the fire could not readily act on it. If 
deposit inside the boiler covers the plug it may melt 
before its time. A fusible plug is also an element of 
safety when there Is danger by excoSsive pressure, for 
as the pressure increases so does the heat of the water 
or steam, and when the latter reaches a temperature 
higher than normal the plug will act. Fusible plugs 
are, of course, no protection when a boiler is weak or 
develops detects in structure. 



Cyclopasdia of Mechanics. 



43 



Fixing Handle of Walking Stick, — It 1b often 
required to fix the horn head of a walking stick or 
umbrella to an Iron screw dowel that is firmly fixed 
in the, stick itself, the joint being covered by a 
silver band. As a rule, the hole in the horn handle 
has worh too large for the dowel screw to grip, and if 
so a new screw of larger gauge is necessary. Screw 
the horn on the screw first. If the screw is tight and 
there seems danger of splitting the horn, warm the 
screw in a flame and screw home whilst hot, and then 
immediately immerse in cold water. There is no cement 
that will make a firm .ioint. A wooden plug might be 
tried, but it will be difficult to get the .old screw into 
it, as the plug will probably wind out. Fill the Silver 
mount with wax cement or sealing wax, and screw the 
handle up tight whilst the wax is fluid. 

Stocks for Shoeing Kicking Horses.— Fig. 1 shows 
side elevation, and Fig. 2 end elevation, of a set of 
stocks for use in shoeing horses that kick. The ground 
is marked out to Figs. 1 and 2,.and 7-in. square posts A 
a,re sunk in each corner. It the stocks are put up in 
A building or against a wall th^re must be clearance 
<say 2ft. or 3tt.) in front for the horse's head. Two cross 



the edge, of the mount), and place it on a few thick- 
nesses of blot'tiug-paper in a beaker or saucepan. 
Pour warm water over the lens and keep warm for a 
time ; this will soften the balsam, and the lenses may 
then be Carefully slid apart. Note the positions of 
the lenses, so that in putting them together again 
the same -sides of the lenses as before may face each other. 
Clean the lenses with benzole, ^ow place a lens, concave 
surface up, on a warm plate, and drop into it a spot of 
balsam free from bubbles, and lower upon it the convex 
surf a ce of the other lens, and gently but firmly press well 
together till the excess oozes out. Put in a clamp or 
bind up together until dry. On heating, the balsam 
should remain hard. On resetting the lens, the fungoid 
appearance will most likely have disappeared. 

Gums used by Frencb Polishers.- Shellac forms 
the foundation of most polishes and spirit varnish. 
Garnet lac is a very dark variety useful for "black" 
or varnish for japanning ipurposes. Orange shellac has 
many grades, from common to best. Lemon sheUac 
is for best work. White or bleached shellac is used 
for decorative work, such as polishing inlaid work 
and fancy woods that are to be kept light in colour. It 




ipE 



Stocks for Shoeing Kicking Horses. 



ffails B (Pig. 2) are fixed in front, and, if desired, movable 
ones at the hack, similar to rails seen in stable stalls. 
The top cross rail in front should come just under the 
horse's chest. There are also two rails C (Figs. 1 and 2) 
at each side, as shown ; also a roller D (Fig. 1) on the 
near side, and a centre rail E (Pig. 2) opposite on the off 
aside i the sheet or webbing is strapped round the rail 
and made a fixture on the roller so that a man at the 
front and one at the back working the roller lift the horse 
off its feet, which are strapped to the rings shown 
at the bottom of the posts. 'The roller is turned with 
iron pins F (Pig. I), like those seen on knacker carts. 
The bow seen at the top of the front posts is of iron. 

Blackening Brown Boots.— To blacken brown boots 
and shoes, first clean off all the dye with a strong solu- 
tion of hot soda water, using a tooth brush. When the 
•dye is removed, rub with a little black dye, which can 
be bought at most boot repairers' or grindery shops 
(a pennyworth will be ample). Allow this to dry, rub 
with a bit of pork fat, which makes the leather soft, and 
afterwards give the boot a good blacking and polishing. 

Taking apart Photographic Lens. — The balsam 
■used as 'cement between two photographic or other 
lenses sometimes assumes a sort of fungoid appearance. 
This, if sligh'., will practically make no difference to 
the working of the lens, but It may be removed 
as follows. Take the lens from its mount (and 
•this removal may necessitate the turning up of 



is best to mix the lac when in solution. Gums such as 
benzoin, sandarach, and mastic are not absolutely 
necessary in polishes j their object is to gain a bright 
surface with a minimum of trouble. The addition of 
such gums and resin converts a simple polish, easy to 
manipulate, into a varnish diificult to use witb a rubber 
without an undue quantity of oil. 

Using Mixed Jet for Umelight.— A mixed jet can 
be nsed for oxygen and coal gas, and the light would be 
about the same as a blow-through jet with the same 
gases. The hydrogen should be rather more than 2 
to 1 of oxygen, and the beat proportion is being used 
when the best light is obtained. With coal gas and 
oxygen, use about 10 of gas , to 8 of oxygen ; here, 
again, turn on the oxygen till the best light results. It 
oxygen cannot be obtained at a definite pressure from a 
bag, fill a bag with coal gas also, and leave both in 
a'double set of pressure boards under the same pressure. 
Falling this, the pressure of oxygen will commence at 
9 in., and will gradually fall to notmng. With an oxygen 
cylinder the pressure can, be regulated to about that of 
the gas. For preparing oxygen, 2 parts of chlorate to 1 part 
of oxide of manganese are heated in a retort. Wright 
recommends 21b. of chlorate to ilb. oxide of manganese 
and 6 oz. of common salt, because the oxygen comes off 
from this mixture very regularly, lib. of the first mix- 
ture yields about 4,801) cub. in. of oxygen, and 1 lb. of the 
second mixture yields about .5,000cnb. in. To compress 
the mixture, powder and moisten it with water first. 



44 



Cyclopaedia of Mechanics. 



Mechanism of Perpetual Calendar Watch.— Pi^. 1 
shows the arrangement ot a perpetual ' calendar dial. 
At the top is the month hand; on the right ia the date 
hand; on the left is the day-of-the-week hand. Inside 
the seconds dial is the moon disc, showing by observa- 
tion or by the nnmbers the age ot the moon. Pig. 2 
shows the mechanism underneath the dial. D Is the 
moon disc. It has two moons, and around its edge are 
flfty-eisht teeth, going round once in two lunar months. 
It rides loose upon a central pipe, and is driven, one 
tooth each day, by a pin in the wheel E', driven in 
its turn by the wheel r. P is on the hour wheel of the 
watch, and goes round once in twelve hours ; it has forty 
teeth. It drives the wlieels E' and E-, having eighty teeth 
each, and going round once in twenty-fonr hours. The 
wheels E' and E", by means of pins projecting from them, 
as shown, drive the day-of-the-week wheel B and the date 
wheel one tooth each day. B has seven and C has 
thirty-one teeth. The day-oi-the-week hand is fastened 
to the axis of B, and the date hand to the axis of C. A Is 
the month wheel; it has forty-eight teeth, and goes 
ro\jnl once in four years. It is driven by the inter- 
mediate wheel O, driven in its turn by the date wheel C. 
Upon A is mounted a steel disc having notches of vary- 
ing depth in its circumference. Thus, the space repre- 
senting the month of January is high : February is a 
deep slot, as it is three days short j March, again, is high ; 



to A, and caused to return, when drawn back each day, by 
a steel spring, as shown. The month wlieel A, day-of-the- 
week wheel B, date wheel C, and moon disc D are all held 
in position by spring flirts resting between their teeth, 
and causing them to jump one tooth accurately each- 
time they are moved. This is but one of many forms 
of perpetual calendar movements. All are complicated, 
and difflcnlt to make, and even when properly made fre- 
quently give trouble. 

Cnring Birds' Skins.— A preservative used in curing 
birds' skins consists of lilb. of whiting and ilb. of soit 
soap boiled in 1 pt. of water, with the addition of i ot. 
of chloride of lime and ioz. of tincture of musk. This- 
reclpe works out at less than a farthing for a starling or 
blackbird. Instead of musk, tincture of camphor might 
be used ; it is a little cheaper but not so good. In using- 
the preservative it is painted on the inside of the skins ; 
then the " stuffing " is done. 

Polishing Ebony Fretwork.— The polishing should 
be wholly or three parts done before the fret-cutting is 
begun. After sawing tire wood, fix It to a firm flat bencli> 
and plane the surface smooth ; then proceed with the cut- 
ting, drilling the entering holes for the saw from the face. 
Ordinary work may be nnished by using various grades. 
ot emery cloth down to a fineness of 00, the final polish" 




Fig. I 



FIG. 2 



Mechanism of Perpetual Calendar Watch. 



April is a shallow notch, being one day short i and so on. 
It will be noticed that three Pebruaries are deep notches 
(three days short, or twenty-eight days) , and one Febru- 
ary is not so deep, being two days short, or twenty-nine 
days in leap year. The lever 11, a finger on which enters 
these notches, regulates the number of days shown for 
each month by operating on a projecting pin on the date 
wheel C. The position of the lever H with regard to the 
wheel varies according to whether its finger piece rests 
in a deep or a shallow notch of A. Thus, when resting on 
a high space, or a thirty-one-day month , the cam shown on 
C passes the lever without disturbing it at the end of the 
month. But when the lever His resting in a notch, it pro- 
jects farther over C, and the cam comes in contact with it 
one, two, or three days, as the case may be, before the 
end of the month. The pressure on the cam causes the 
pin in C to rise and come in the path of the lever H, as 
the latter is drawn back each day by the Impulse pin in 
E' acting on the arm I. Each day when the arm I is 
released, H springs forward again and ordinarily does 
nothing, as there is no projecting pin on 0; but after 
the cam on has come in contact with H, the impulse pin 
C is caused to ripe, and the lever II coming forward forces 
C round for several teeth. The wheel C is a delicate piece 
of work. There is ;i connection between the cam upon 
it and the impulse pin upon which the lever H acts. 
The contiection is underneath the wheel, and consists of 
a spring lever. The effect is that, as soon as the cam 
presses against the end of H, the Impulse pin rises from 
the level ot the wheel and stands up in the path of H. 
It remains in this position until about the middle 
of the month, when it comes into contact with a 
fixed stud under C, and Is restored to its nortnal 
position level with the surface. The lever U is kept up 



being given by brislily rubbing with a hard brush oi» 
which has been placed a little beeswax. Or the following 
process might be tried. Wrap the emery cloth tightly 
round a piece ot cork 4 in. by 2 in. by I in., and rub up- 
and down with the grain of the wood. Great care must 
be exercised so as not to break off any portion of th& 
more delicate fretwork, and change the gnide of the 
emery cloth as the surface gradually becomes smoother. 
Should it be preferred the surface may be lightly French 
polished, usmg silk for the outside of the rubber in 
place of ordinary cotton ; silk will last longer over the- 
sharp Burfa.ce of the fretwork. 

Fhotograpblo Vignettes.— Plashed glass is used fov 
making photographic vignetting glasses, the colour 
being removed from the centre by rubbing with hydro- 
fluoric acid. The operation is a messy one, however. 
Cardboard is by far the most convenient material to usff 
for making vignettes, as a fresh one has generally to be 
cut for each negative. It is not necessai-y to keep a 
card vignette moving whilst the negative is printing. 
The usual plan is to shape the vignette according to the 
density of the different parts of the negative, to fix it at 
a greater or less distance from the negative, and, if 
necessary, to cover it with tissue paper. Many 
failures have been due no doubt to fixing the card too 
near the negative; it should be more than iin. away, 
and should lap over where the negative is thin, for there 
the light will spread rapidly. Sometimes it Is advisable 
to tuck a little cotton-wool under the vignette, giving a 
loose edge to the wool to avoid a hard line. To make a> 
successful vignette by any method the baolcground 
must be light; but vignetting is old-fashioned nn* 
seldom artistic, and should be avoided if possible. 



Cyclopaedia of Mechanics. 



45 



KnamelUng and Folisblng Slate. — The slabs of 
-elate are cut to size, shaped, moulded, carved, or 
incised as may be required, then polished with sand 
and water to a ilne surface. The enamel is then care- 
fully and regularly laid on, or the slab is marbled to 
a design, then Rtoved in an otcu capable of being heated 
to y60° P. Some colours require less heat than others. 
The time necessary tor stoving depends on the colour; 
experience will teach this. The colouring is then 
polished with rottenstone and sand and, when a very fine 
finish is required, completed with the hand. 

Pattern for Conical Rim.— It is assumed that a copper 
hoop is to be put round a wooden bucket to ornament it. 
Below is explained how to draw a plan to which to cut the 
•copper so that it will fit snugly to the shape of the bucket. 
The pattern wanted is a frustum of a right cone, and 
to set this out to the correct taper first draw a semi- 
elevation of the bucket as ABDC (Fig. 1). Next draw 
the position of the rim V P e E, and from E draw a line 
E f at right an gles to B e, and draw P f '. "With f as centre, 
■and with f' 1? and /' f as radii, draw quarter circles F L and 
/ J to represent a quarter plan of the rim. Divide these 
quarter circles into an equal number of parts, as F, G, H, 
f, q. h, etc. Join Vf,G ff, etc., and also join P 9, Gft, etc., by 
dotted lines as shown. The lines T>f,ag,llh, etc., will be 
the plans of a series of slants of the cone, and the dotted 
lines F B, etc;, will be the plans of a series of diagonals. 
i' £ is the slant of the frustum, and to find the slant of 




of animal-3, but a small consumer will iind egg albumen 
more suitable. The albumen of one egg will coat two 
slieets of paper, but to cover the dish that must be used 
to the depth of about iin., about twenty eggs will be 
required. The paper may be coated in quarter sheets. 
The whites of the eggs must be thoroughly separatedlrom 
the yolks, no trace of the yolks being in the coating solu- 
tion. Tap the shell on the edge of a cup to crack it, hold the 
crack uppermost, and, placing the thumbs in the crack, 
pull in two and pour the yolk from one half shell to the 
other. While this is being done, the white will of itself 
f aU into the cup below. Pour the whites one by one into 
a deep vessel, add 8 gr. per ounce of ammonium chloride, 
and beat to a, froth with an egg whisk or a bundle of 
quill pens. Allow the mixture to settle till next day, 
niter thi'ou'gh fine muslin, pour into a flat dish, and, to 
coat the paper, which is more easily done it it is slightly 
damp, float it on the solution, lowering the paper at one 
corner, and pushing it forward along the dish until the 
whole surface is in contact. Care must be taken to 
avoid air bubbles, as such spots cannot be sensitised. 
If the paper is at all dry it will curl back off the solution. 
The paper may be tinted with Judson's dyes, it desired. 
For double albumenised paper, immerse after the 
flrst coating in a. solution of 4 parts methylated spirit 
and 1 part water, then give a second coating of albumen. 
The paper is sensitised just before use by floating on a 
solution of silver nitrate 50 gr. to the ounce. 

Defects of Gas-meters.— When the floats of wet gas- 
meters are being soldered together, the air inside the 
floats becomes rarefled owing to the increased tem- 
perature caused by the heat ot the bolt used in solder- 
ing. When this inside air is cooled by the water in the 
meter, the pi'essure ot the outside air upon the float 
becomes so great that any sudden slight Increase ot 
pressure will frequently overcome the resist&nce of 




Fia 2 



Pattern for Conical Rim. 



the diagonal draw a line ff m at right angles to the dotted 
line F g, and make g m equal to the line E /. Draw F m, 
which will be the true slant of the diagonal. To work 
the pattern, take the length F E and set off on a straight 
line as Wfon the pattern (Fig. 2). Now take the true 
slant F m (Fig. 1) of the diagonal as radius, and using F 
(Fig. 2) as centre, draw arcs to cut qg on each side of the 
centre line. With f g (Fig. 1) as radius, and f (Fig. 2) as 
centre, cut the arcs flrst drawn. Again use the slant F f 
(Fig. 2) as radius, and with the intersecting arcs fl ff as 
centres, describe arcs at the top of .the pattern (Fig. 2) . 
With F G as radius, and F as centre, cut the arc last 
drawn. Kepeat this method of working for each division 
on the plan (Fig. 1), using the small and large divisions 
and slants and diagonals in their proper order, and make 
the number of divisions on the complete pattern equal 
to four times the number on the (juarter plan ; or if the 
rim is made in two pieces the divisions would be as shown 
by the accompanying patterns. 

Making Sbaving Faste.-^Shaving pastes are made, 
as a rule, from fine soft soaps composed of potash and 
lard. To make cr6me d'amande, dissolve lib. of caustic 
potash in 1 pt. of water. Melt down in a pan 3 lb. ot 
lard and add to it gradually the potash lye, stirring 
thoroughly during the addition. Boil and stir well for 
some time, and continue adding the lye untU the mass 
becomes pasty, and a small portion taken from the pan 
works smoothly and free from greasiness when it is 
dipped In water and worked between the fingers. The 
addition ot the lye may then be stopped. Beat the soap 
in a mortar and with the pestle till it is cold, when it 
will have a satiny appearance. Add sufficient essence 
of almonds during the beating. 

Making Albumen Paper.— Albumenised printing- 
out paper is made by coating a suitable paper with 
albumen containing a soluble chloride. Eives paper 
is generally employed, and what is known as 10 kilo 
should be chosen. Most of the albumen Used com- 
inerjially for this work Is obtained from the blood 



the metal, which is only soft pewter. Floats should 
always be made with egg-shaped ends instead of fiat 
ends, so as to offer more resistance. In dry gas-meters 
the faces of the hard white metal valves sometimes 
become coated with a deposit, caused probably by 
the action of the gas on the oil used to keep the 
diaphragms soft. In course of time this deposit liardens 
until the pressure ot the gas is insufficient to move the 
valve cover. The top of the meter and the top ot the 
valve-box inside should be taken off, and the valve covers 
taken out and thoroughly cleaned with a little naphtha, 
the faces of the valves being treated in the same manner -, 
the meter should then be put together again and be re- 
tested and stamped by an authorised inspector. The 
only remedy is to soften the diaphragms with an oil that 
is not affected by the particular gas in use. 

Manufacture of Lucifer Matcbes.— The tipping 
composition for " strike-anywhere " matches consists ot 
red phosphorus with other ingredients as follow. (1) 
Phosphorus 1 part, chlorate of potash 8 parts, glue ' 

4 parts, whiting 2 parts, powdered glass 8 parts, water 
22 parts. (2) Phosphorus 2 parts, chlorate of potash 

5 parts, glue 3 parts, red lead 14 parts, water 12 parts. 
Safety matcheshave no phosphorus on the tip, but itis con- 
tained in the rubber. For tipping safety matches, use (1) 
Chlorate of potash 1 part, glue 2 parts, sulphide of anti- 
mony 1 part, water 12 parts. (2) Chlorate of potash i parts, 
bichromate of potash IJ ^arts, red lead i parts, sulphide 
ot antimony 3 parts, with sufficient glue and water to 
form a paste. The rubber on the box is treated with 
phosphorus 2 parts, powdered glass 1 part, mixed with 
sufficient glue solution to form a thin fluid while warm. 
Eed phosphorus varies in colour from red to brown ; it is 
formed by heating the ordinary phosphorus to 240° C. or 
250' C, either in a closed space 01' in an inert gas, such as 
nitrogen or carbonic acid. On heating the red modi- 
fication to a temperature of 260° C. it changes back to the 
ordinaryphosphorus.Kedphosphorus.whenfreed from the 
ordinary phosphorus, is non-poisonous, passing through 
the body unaltered; but red phosphorus is rarely. If 
ever, free from ordinary phosphorus, and hence cannot 
be said to be non-injurious. Eed phosphorus does not 
take flre by simple friction like the yellow variety, but 
must be raised to a temperature of 210° 0. 



46 



Cyclopaedia of Mechanics. 



Lenses for Magic Lantern. — Plano-convex lenses 
are generally xised in magic lanterns, two to each con- 
denser, with their convex sides towards each other. 
The smallest condensers used are iin. In diameter, 
and this is none too much, as the slide pictures are 
supposed to be iin. in diameter. A single lantern 
should have a condenser not less than Win. in diameter. 
Biunials and triples require 44-in. condensers to allow 
for the rolling ol the curtain, and also a little margin 
to get the two or three discs coincident on the screen. 
For the objective, the following lenses ai-e required :— 
The front combination consists of a double convex lens 
and a plano-concave lens cemented together. These 
should be 15 in. to IJin. in diameter. The back combina- 
tion has two lenses separated by a short space ; the one 
nearest the front is a meniscus, with the convex side to- 
wards the front, and the other is a double convex lens of 
unequal curves, the curve with the longer radius being 
placed nearest the light. These lenses should be 2 in. in 
diameter. An objective of this description has a focus of 
about 6 in. and gives the best results. When, however, 
an objective of very long focus is required, a single 
achromatic answers nearly as well : but it must be suffi- 
ciently large to take all the rays of light. A single lens 
of 12-in. focus should be at least 3 in. in diameter. 

Constructing a Bamboo Bedstead.— Fig. 1 shows 
the foot of a bamboo bedstead, 3ft. wide and 3ft. 10 in. 
high ; Figs. 2 and 3 are klternative designs for the head. 
The framework qt each of these sections must be made 
from canes If in. to 2 in. in diameter, and great care 



hand when it is ready for moulding. For this, «*» 
an iron mould with a plug attached to a handle. Tlin- 
mould should be filled witli the clay and the plug ham- 
mered in, to form the hollow of the crucible. It is kept 
In a warm place for a few days, when the crucible will 
leave the mould, and may be turned out. It is dried in a 
warm place for several ceeks, and gradually heated when 
it is used for the first time. 

Varnishing Photographic Negatives. — The re- 
touching of a negative should always, if possible,, 
be done before varnishing, such portions of the nega- 
tive as are to be operated on being covered with a 
retouching medium. This medium may be purchased, 
or may be made of gum dammar 9S gr, turpentine 1 oz. 
If it is preferred to varnish before retouching, the 
varnished negative must be rubbed down with powdered, 
resin to give a surface on which the retouching pencil 
can be used. The following varnish is recommended. 
Sandaraoh J oz., seed lac i oz., castor oil 80 drops, 
oil of lavender 40 drops, alcohol 10 oz. Powder the 
resins and dissolve in the alcohol, and add the rest 
of the ingredients. "Warm the negative tUl it is as hot 
as can be comfortably borne by the back of the hand. 




Constructing a Bamboo Bedstead. 



must be taken in making the joints and seeing that 
the dowels are a good fit. A (Figs. 1, 2, and 3) is a piece 
of beech 7 in. wide and U in. thick. This must be fitted 
in position 1 ft. above the ground before the filling work 
Is commenced, and should be securely fastened with 
round-headed screws passed through the legs and cross 
rails into the wood. The strength of the bedstead in a 
great measure depends on the firmness of this piece of 
wood, as on it are fastened the angles by which the 
head and foot are stretched. The filling work can next 
be proceeded with, care being taken that every joint Is 
strong and a perfect fit. Fig. 2 shows a design suitable 
for an upholstered back, 7ft. 9 in. high; if preferred, 
similar work to that shown in Pig. 3 can be used. 
For the bedstead bottom, iron fittings similar to those 
used for wood bedsteads are advised. Fig. 4 is a sketch 
of the iron angle, and B (Fig. 2) shows the position 
in which the angles are placed. They are securely 
fa-itened to the wood with screws, and the stretchers 
and laths are attached in the usual manner. 

Bemovlng Stain from Polished Wood.— A soda- 
water stain on polished wood should be wiped over with 
linseed oil as soon as noticed. If left nnoiled, the only 
aliernatlve is to repollsh, first removing the damaged 
poiish by rubbing with No. 1 glafspaper and oil. It this 
treatment is not a success, use spirit instead of oil. 

Making Plumhago Crucible!- In making a ci-uclble 
with a quantity of plumbago dust, mix the plumbago 
with an equal weight of fireclay, and add water while 
kneading to form a stiff dough. Keep this in a cool 
place for a few days, and work it from time to time, 
when it will become less sticky and more plastic i 
the clay should be almost too stiH to work by the 



pour a pool of varnish in the centre of the plate, ani 
let it Uow first to the top right-hand corner, next to tlie 
top left-hand corner, then to bottom left-hand corner, 
almost touching the thumb, and ^our ofl! the excess at 
the bottom right-hand corner into the bottle. The 
negative should not be rocked. If the varnish is inclined 
to be streaky it is too thick, and more alcohol must bo 
added. Conduct the whole operation as slowly as 
possible. Drain thoroughly, and bake the varnlsheil 
negative in front of the fire or over a gas jet till the 
varnish is quite hard. Heat the negative evenly or lb 
wUl crack. The negative should be held by the extreme 
corner with the thumb and forefinger of the left handi 
unless it is larger than half plate. 

Colouring Gold.— The simplest method of colouring 
gold jewellery is to bring it to a uniform heat, allow 
to cool (and thus become annealed), and then boil 
until bright in a pickle of 8 oz. of rain water and 
loz. of sulphuric acid. Another method Is to anneal 
the gold, boil it in a pickle of nitric acid and water, 
again anneal, and dip in the following colouring mix- 
ture. Two parts (by weight) of saltpetre and 1 part 
of table salt are heated in their dry state in a colour- 
ing pot or blacklead crucible ; when hot, make Into 
a paste with hot water, boil, add 14 parts of muriatic 
acid, and stir well. Use at boiling point; leave the 
gold in the solution for not more than 90 seconds, 
as the solution removes more or less of the gold. On 
taking the gold from the colouring solution, rinse it 
in a pickle, dip it in hot water, and dry In hot sawdust : 
the gold will be spotted if not thoroughly dried. Thl8 
method may be used with gold ranging between 12 and 
20 carats fine, the best results being obtained witb 
15-carat gold. 



CyclopEedia of Mechanics. 



47 



The Preparation of Chromic Acid.— Chromic acid 
(H2Cr04) is produced by two or three methods. In 
one, 2 parts (by measure) of a cold saturated 
solution of bichromate of potassia are mixed with 
3 parts of sulphuric acid; on cooling, the chromic 
acid is deposited in crystals, the motlier liquor being 
then decanted. Perliaps the method of producing 
chromic acid more generally followed commercially is 
to decompose chromium sulphate with lime and to heat 
to redness the resultant paste of lime, gypsum, and 
chromium oxide. The chromate of lime formed is 
treated with sodium sulphate to yield soluble sodium 
chromate and gypsum. The addition of sulphuric acid 
liberates the chromic acid. A less wasteful process than 
this is the electrolytic one now being worked in Germany 
by Lucius &, Bruning. In a solution of chromium sul- 
phate in sulphuric acid are immersed both lead anode 
and lead cathode, chromic acid being liberated on the 
former and hj'drogen on the latter. A current at 3'5 
volts with a current density of SOUampSres per square 
metre is required, the cells being at the temperature of 
60° C. (122° P.). 

Making a Bone Apple-scoop.— In every sheep there 
are two bones specially suited for making apple-scoops, 
and with them only a small amount of trouble is 
left for the workman. The shank, bones of Welsh or 
othermountain sheep are generally preferred for scoops ; 
they make neater articles. But for larger scoops the 
shank bones of sheep of the larger breeds come in 
handy. To clean the bones, boil, say, for from half to three- 
quarters of an hour ; too much boiling is liable to cause 
the head of the bone to slip off. With a tenon saw or a 
butcher's meat saw, on the fiat side of the bone, as at A 




Fig, 2 
Making a Sons Apple-scoop, 



(Pig. 1), make a shallow cut just deep enough to reach to 
the hollow containing the marrow. Wext saw off the 
lower end of the bone, as at B. All the bone from the 
middle of the front between A and B has then to be 
chipped out. Por this purpose, use a J-in. gouge, and 
afterwards a small chisel driven with a mallet s or a knife 
can be used, but then the work will take much longer. 
To cut the bone now left remaining to the shape of 
Fig. 2, use a half-round file. The two sides of the front 
and the circuit of the point must be brought to a sharp 
edge, as by 'these the apple is cut. Whilst the bone is 
being worked it will be sure to show more or less 

frease; this can be removed by a ragdipped in whiting, or 
y a orumpled-up piece of blotting paper. To extract the 
marrow from the hollowabove A (Pig. 1) ,use a bit of crooked 
wire and a few small rolls of blotting paper. The opening 
should then be stopped with a neatly-fltting, piece of 
cork, tucked in tightly. To finish, smooth the bone with 
glasspaper and polish with whiting. 

Putting Sash Lines in Window Frames.— Before 
beginning to replace broken sash lines, carefully lower 
the top sash to see whether the breakage is at one 
or both of the lines. The i-in. bead of the side at which 
the line is to be restored must be removed, a blunt 
chisel being used ; a broad chisel bruises less than 
a narrow one. Begin the prising of the bead from the 
back, as, though the paint must be broken, it need not 
be defaced more than necessary. The lower sash can 
then be removed and the old line cleared with pincers or 
a blunt chisel. If the upper sash line is broken it is often 
best first to remove the line from the lower sash so that 
it may be put out of the way. The parting bead must 
next be removed, and pincers are better than a chisel for 
this. Sometimes a chisel, used to cut the paint at the 
lower half of the bead, is an advantage. Remove the 
pocket piece and take out the weight and old cord. If it 
is difficult to remove the weight, it is sometimes possible 
to tie a new line without removal. The new line is 
passed through the sash pulley by means of a " mouse," 
a piece of lead not thicker than the line and about 2 in. 
long, to which a fine strong twine is affixed j the twine is 
hitched to the sash line twice or thrice and the mouse is 
entered through the pulley, drawn through the pocket, 
and the line pulled through by its aid. If the weight is 
BtUl in the sash frame, the line can be inserted in the 
weight by drawing through the mouse and making a 



knot. Lift the weight as high as possible and fix the 
line so that the sash will just reach the sill. Superfluous 
line is often a hindrance to proper workiug of windows, 
as the line always stretches in use. The replacing of the 
pocket piece can be done before the liue is fixed to the 
sash, and, in the case of the lower sash, the parting bead 
can also be put in. The 8-in. or stop bead should be 
sprung in by getting nails nearest the ends in first. 
Sometimes they will need shortening, but no nails 
ought to be removed, and all should be guided to their 
holes, first those nearest the ends, and then those at the- 
middle. If needful, a nail or panel pin may be inserted, 
but this is not necessary unless the bead springs away 
from its place. Care must be taken to strike on thdold 
nails or the stopping will come out and the bead be 
made unsightly. 

Condensation from Under Side of Iron Roof.— The 

drbpping of water from the under side of a corrugated 
iron roof is caused by the moisture of the warm atmo- 
sphere of the room condensing on the colder surface of 
the iron roof, and this condensation, of course, goes on 
more rapidly during frosty weather. The remedy is to fix 
at the bottom of each sheet of iron a small half-round 
gutter to catch the water. Lead it to one end of the- 
roof, and bring it to the ground by a down pipe. A lining 
of slag wool or silicate cotton supported by matchboard 
will prevent the condensation sometimes. 

Ho-nr to Set a Kuling Pen.— By taking out the screw 
of the ruling pen and looking directly at the point 
of the pen, it will be seen whether the worn point has a 
flattened surface. If so, place the pen on au oilstone (fine 




Method of Setting a Ruling Fen. 

Turkey preferred) in the position shown in the sketch, 
apply a little oil, move the pen backwards and forwards 
at the same time slightly rocking it horizontally and 
vertically. Wipe and examine the pen occasionally, and 
stop just short of bringing the point to a sharp edge. If 
one point of the pen has been injured and is stiortei* 
than the other, hold the pen upright on the stone and 
grind both points level before removing the screw and 
setting the pen. If the points are, too sharp, the pan will 
out the paper, and it will be necessary to take off the 
keen edge by using it for a few minutes on a piece of 
brown paper. 

Making Photographic Printing-out Paper. — No 

one, unless he is likely to be a large consumer and 
able to afford a proper apparatus, should attempt to 
make P.O.P. The paper is sold so cheaply that it could 
only be made in large quantities at the same price ; and 
expensive plant and long experience are necessary to 
ensure good results. Prepare two solutions. (A) Ammo- 
nium chloride 50 gr.. Nelson's No. 1 gelatine 160 gr., 
Heinrich's hard gelatine 3(0 gr., distilled water 20 oz. 
(B) Silver nitrate 150 gr., distilled water i oz. Dissolve 
the gelatine in 4iOZ. of water, warm and add the re- 
mainder ; then add solution (B) a little at a time, stirring 
thoroughly between the additions. Allow the emulsion 
so formed to set, then wash by squeezing througli 
mosquito netting, and washing or soaking in a few 
changes of distilled water. The slireds must then be 
well drained, melted down, and the emulsion is ready for 
use. The paper is unrolled over the surface of , the 
emulsion, which is placed in a trough or a dish tilted to 
an angle. 

Cutting Blinds.— Linen or art print blinds are cut 
upon a large flat table, using a long straightedge and 
marking awl. Equal width at top and bottom can be 
secured by folding the stuff so as to prick both at once ; 
squaring must either be done by a large square working 
on a trued edge of board or by folding the blind (when 
made parallel) edge to edge and pricking through. Lines 
are made witli a marking awl, and for cutting some use 
shears, others a knife and straightedge. Whenever 
possible, cut off the selvedges. Blind cloths vary in 
width ; prints are made in every 6 in. from 3i) in. to 60 m. ; 
unions in almost every 2 in. in saleable widths. 



48 



Cyclopaedia of Mechanics. 



Making Cells for Optical Work. — By following 
these Instructions amateurs who haye a small lathe 
not adapted tor sorew-eutting, and who are not 
adepts in the use of chasers, can make the brass cells 
and similar work for microscopes, telescopes, etc. 
The apparatus here described will turn and cut the 
threads without displacement, thus ensuring perfect 
■centreing, without which the best lenses will give un- 
satisfactory results. To hold the cells, etc., use box- 
wood chucks fixed on iron face-plates. A hole Is 
drilled truly in the centre of the chuck while In the 
lathe. Into this hole fits a turned Iron or steel mandrel 
of the shape shown at Figs. 1 and 2. The part O should 
be a tight working fit in the boxwood chuck. The poppet 
end of the mandrel has a thread cut on it of a pitch suit- 
able for optical work. Fig. 3 shows the complete mandrel 
and tool-i-est. The hole B (Fig. 2) is tapped to receive 
the screw that regulates the cut of the tool, while into 
the hole A (Fig. 2) slides the guide ; and the set-screw 
E (Fig. 3) takes up any shake in the rest. To complete 
the tool-rest, pieces ¥ (Pig. 3) to carry the tool and G for 
the handle end will be required. The ordinary poppet 
must be discarded j in Its place use a wrought- or cast- 
iron poppet, made as shown in Figs. 4, 5, and 6. The 
tole II (Figs. 4 and 5) receives the bush I (Fig. 6), 
which is drilled and tapped to suit the screwed end of 
the mandrel M. J and K are nuts, and L is a handle 
made fast to the mandrel ; It actuates the cut of the tool 
longitudinally. N (Figs. 4, 5, and 6) is the hole iised for 
bolting down the poppet, "When facing, boring, or turn- 
ing a cell, etc., the nut J is released and the nut K is 



A B 



\Q 9i 



■nil 



FIG. 2 



rrw 



1 J ^ ■ ; BiliWiWilillWWijlil 



^ 



jammed ; then I can revolve, the out being regulated by 
the handle L. When thread-cutting, the lathe spindle 
carrying the chuck must be fixed sothatit will notturn ; 
then the nut J is jammed tight, thus fixing I, the cut being 
actuated by the handle L. The thread may be started at 
any point desired. Fig. 7 shows the complete apparatus, 
with letter references as before. If the use of a lathe is 
not to be had, the apparatus will still be of use, but in 
that case all operations of turning and screw-cutting 
must be managed by the handle L, while the work 
lemains at rest. The sketches are not to scale, and the 
apparatus must be made to salt the lathe in use. 

Tbe Manufacture of Glue.— Glue, size, and gelatine 
are varieties of the same substance ; they differ only 
in the quantity of moisture and of impurities which 
they contain. Glue contains so many impurities 
that it is unsuited for use other than as an adhesive 
for wood, paper, etc. Gelatine-yielding substances are 
legion, those in commercial use including the skins 
of all animals, tendons, intestines, bladders, bones, 
lioofs, and horns. In the preparation of ordinary 

Elue, great use is made of the parings and cuttings of 
ides from tan-yards; tanned leather is useless for the 
purpose. Brietly, the process consists in boiling the 
animal matter and straining the product into coolers, 
where it thickens into a jelly. This is cut into sheets or 
mitable thickness and dried in the open air on frames of 
wire netting. Spring and autumn are the most suitable 
times tor drying the glue, the frost of winter and the 
dry heat of summer having injurious effects. The size 
is not dried, but is sold just as it is cut from the coolers. 
In making size and glue from shredded skins (chiefly 
those of rabbits), the processes in vogue at a large 
factory in America are as follow. 350 lb. of shredded 
skin and about 400 pailfuls of water are put into a 
wooden vat and boiled for two hours, the material 
being well stirred every fifteen or twenty minutes to 
prevent it settling. The liquid is then run off from 
the bottom of the vat and strained in a press which 
may be about 4ft. square, 3 ft. high, and made of wooden 
slats. The interior of the press is lined with bagging, 
and through this material the liquid is strained or 
pressed by means of a hydraulic jack. The hot sti-ained 
liquid drops into a vat below, whence it is conducted 
by means of hose into barrels. In from eight to ten 
hours the stuff is cool, and has a skin formed on the 
top ; in warm weather ice is laid on this skin to harden 
it; this is size. For making glue, the strained liquid 



is run into coolers, these being wooden troughs lined 
with zinc, and in twelve hours' time the material, then 
in the form of jelly, is loosened from the trough by 
running a wire along it, the wire being bent to con- 
form with the rectangular section of the trough. The 
block of jelly is cut up into cakes, and these are 
then sliced in an arrangement of fine wires stretched 
tightly across an iron frame about iin. apart; this 
frame is drawn through the jelly. The drying frames 
upon which the slices of .ielly are then placed are about 
5 ft. 6 in. long and 2ft. wide, and are made of galvanised 
wire netting. The frames, when full, are placed in 
racks through which the air can circulate freely. It 
takes but a few days for the jelly to dry in a cool west 
wind, though a system of artificial drying, by means or 
which the size becomes glue in but a few hours, is now 
being practised. In drying, the material shrinks to one- 
halt its former bulk. The hard glue is now washed to 
remove dust, etc., and to pi-oduce a glazed ai)pearance. 
In some factories the cakes of glue are cut up into small 
pieces by means of two rotary knives, each making 
300 revolutions per minute. First the glue is passed 
between two4-in. toothed rollers which hold it in position 
and draw it forward after each stroke of the knife. 
In England the raw material, before being boiled, is 
limed ; this treatment is not necessary in the case of 
hide cuttings from leather dressers and tanners, scrap 




._, 


H 




N 




— h4-I 



Fig 4 FIG. 5 




Making Cells for Optical Work. 

from trotter-boilers, dry glue pieces and parchment out- 
tings, which are already limed. The liming is eifected 
by soaking the material in milk of lime contained in 
pits. Afterwards it is necessary to remove or kill the 
lime by washing with water in vats or pits or even in 
revolving drums. The lime in old glue pieces is killed 
BuiBciently by the action of the atmospheric carbonic 
acid, the glue being spread out in trays so as to be more 
readily a&ected. In some works the washed materials 
are subjected to heavy pressure, but in others the boUinic 
is proceeded with at once. The boilers or pansgeneraUy 
have each a capacity of several tons. A false bottom of 
bars keeps a clear space at the bottom. In the middle of 
the boiler is a removable vertical framework, and its 
object, like that of the false bottom, is partly to give 
free space, so that the boiling liquid can circulate 
thoroughly, and partly to simplify the straining of the 
liquid. The pans are heated by a fire beneath, by steam, 
or by the two together. In placing the materials in the 
pans, any horn " sloughs " that may be uised are built up 
around the central framework, the rest of the material 
being then put in. During the boiling intermittent stir- 
ring is necessary, and the fat which rises to the surface 
has to be skimmed off. The charge for the paus is in the 
proportion of twelve tons of fleshings to one ton of water. 
On the completion of the boiling, the fire is put out 
or the heat is otherwise removed; a. time is allowed 
for partial settling and cooling, and the liquid is then 
drawn off through a wooden channel from the space 
beneath the false bottom. In this wooden channel are 
lumps of alum, and the liquid glue is conducted to 
cooling troughs, where it is allowed to cool and harden 
into a jelly or size. The succeeding processes by which 
the size becomes glue resemble those practised in 
America and previously noted. The methods outlined 
above admit of endless variations, nearly every manu- 
facturer adopting a system that in some paiticulor 
differs from that adopted by his tellows. 

Soldering Gun Barrels.— Cramps are generally used 
for holding gun barrels together during soldering, al- 
though they can be bound together as a makeshift with 
stout binding wire. The heat is applied with iron or 
copper heaters, which are placed inside the barrels. 
The best flux for the purpose is sal-ammoniac. Baker's 
preparation can also be used as a soldering fluid. 



Cyclopaedia of Mechanics. 



49 



Fixing Needle to Compass Card.— Large compass 
cards often haye two needles, in which case the agate 
cap is fixed in the card. In small cards the agate 
cap is fixed in the centre of the needle. Draw a pencil 
line on the under side of the card from N. to S. points. 
Fix the needle to this with sealing wax or glue, and 
screw or rivet through the card. 

Cabinet for Beadwork.— The cabinet or workbox 
here described is suitable tor holding beadwork articles. 
It can be made of deal, and almost enough wood 
can be obtained fi'om an old cube-sugar boxj this, 
when sandpapered, stained, and Tarnished, will repay 
the time and labour expended. The following pieces 
will be required for the top case A (Pigs. 1, 2, and 3) . 
Two, llHn. by 7 in. by ^in., for the top and bottom; 
two, 10 in. by 7 in. by iin., for the sides; two, lOJin. by 
6iiu. by i in., for the shelves ; one.lOin. by 6iin. by Jin., 
for the vertical partition ; six, 5 in. by 3 in. by J in., for 
the fronts of the drawers; twelve, 6iin. by Sin. by iin., 
for the sides of the drawers; six, 4iin. bySin. by iin., 
for the backs of the drawers. The bottom for the 
drawers should be cut to fit the inside of the framework. 
The racks B (Figs. 1, 2, and 3) are Tin. by Iin. by iin., 
and should have three holes bored in them to hold the 
tools. To make the desk C (Fig. 3) , use two pieces of 
wood, each 15 in. by 4 in. by t in., for the sides ; one piece, 
84in. by 10iin.by-4in., for the top; one, lOJin. by 15in. 
by iin., for the bottom; one.IOJin.by liin.by Jin.,for 
the back; one, lOUn. bySin. by iin., for the front of the 
drawer ; two pieces, I4i in. by 3 in. by i in., for the sides of 



somewhat similar method of preparing crocus is to heat 
sulphate of iron alone in an iron pan ; constantly stir 
with an iron spatula after fusion until it is thoroughly 
dry and drops into a pale yellow powder. This is then 
powdered in a mortar and sifted, placed in a fresh 
crucible, and calcined. On cooling, the crocus appears 
as a red powder. The colour of the crocus varies from 
pale red to brownish red, blue, and violet, the colour 
being determined by the particular degree of heat to 
which it was raised during its manufacture ; the greater 
the heat the darker in color r and harder is the 
material ; thus a pale red (roug^,) is used for gold and 
silver, while violet, known as " steel red," is employed 
for polishing steel. To obtain the best results with 
crocus, it should be ground as fine as possible, and then 
washed with water. Three clean glasses ai-e used for the 
latter purpose, one being filled with water ; a CLuantity 
of crocus is well stirred in with a wooden stick, left to 
stand for about thirty seconds, and the fluid is then 
carefully decanted into the second glass, leaving a sedi- 
ment at the bottom of the first ; after two minutes in 
the' second glass the fiuid is decanted into the third, 
where it is left for several hours to permit the complete 
settling of the powder. The sediment contained in the 
first glass is too coarse to be of use ; that in the second 
Is a ci'ocus of a finer quality ; while that in the third 
is of the best grade. Crocus of varying degrees of fin«- 
ness maybe obtained on this principle. The material 
requires to dry slowly to be fit for use. It is advisable to 
moisten the dried powder with alcohol, and then to 
ignite it so that all traces of fat may be burnt. For this 




FiC. I 



Fia 2 
Cabinet for Beadwork. 



Fig. 3 ' 



the drawer ; and one piece, 10 in. by 3 in. by i in., for the 
back of the drawer. To make the case, nail the top and 
bottom to the sides of the case A (Fig. 1). The partition 
and shelves are notched so that they will fit in flush 
with one another. The partition should be nailed to the 
top and bottom of the case, as should the shelves to the 
sides. The last are nailed to the top and bottom, and 
the case A is fastened to by nails or (preferably) screws. 
The back, when fastened in, holds the top and bottom 
together. In C six holes should be cut to hold the saucers ; 
these should be iin. deep and Iin. in diameter. The 
fronts of the drawers are rebated so that the sides will fit 
into them. After making the drawers, bore a hole in the 
centre of each of the fronts and glue a knob in to serve 
as a handle. The bottom drawer should have a parti- 
tion in the centre, so that there will be a drawer for the 
finished articles; the other part can be used for the 
vrire, etc. It would be advisable to label each drawer 
with the name of the beads it is intended to hold. The 
labels can be of paper glued on, or of tin nailed on ; or 
it the necessary skill be possessed an attempt may be 
made at painting the name on the front of each drawer, 
the black letters being on a rectangular background of 
white. If glue also is, used it will make the case look 
much stronger. 

The Preparation of Crocus.— Crocus is an abrasive 
material used as a polishing medium for many metals. 
By one method of preparing it, a mixture of salt and 
sulphate of iron is put into a shallow crucible and exposed 
to a red heat ; vapour escapes, and the mass fuses. When 
vapour ceases to be given orE remove the crucible and 
allow it to cool. If the heat Is too intense the oxide of 
iron produced wU have a black colour. The mass, when 
eold, is pulverised and washed to separate the sulphate 
of soda. The crocus powder la then to be submitted to a 
process of careful elutrlation, and the finer particles 
reserved for the final stages of polishing processes. A 



purpose the crocus should be contained in an iron pan. An 
excellent crocus powder for applying to razor strops can 
be made by igniting in a crucible a mixture of eaual partis 
of well-dried green vitriol a,nd common salt. Take care 
that the material does not boU over in a pasty state and 
be lost. When well made, out of contact with the air, it 
has the lustre of freshly cut blaoklead. After grinding, 
elutriating, and drying, a powder Is produced that, by 
applying to a smooth buff-leather strap, may form a ser- 
viceable razor strop, or by being mixed with hog's lard 
or tallow may "make a useful polishing paste for many 
kinds of metal. 

Brush Marks in Enamelling.- In using air-dryln'g 
enamels on cycles great difilculty is sometimes experi- 
enced in getting a surface that is entirely free from brush 
marks. Assuming that the enamels are not stoved, the 
trouble may be due to one of the following causes. 
First, the brush may be too stiff; use a very soft 
brush with a big head and long hair. Secondly, the 
enamel may not be suiflclently thinned j add a little tur- 
pentine, when the coat of enamel will be thinner and more 
uniform, but not so lustrous. Thirdly, the enamel may 
dry too quickly; this is often the case with enamel 
paints, many of them showing signs of drying im- 
mediately after they are laid on, and such enamels 
show brush marks very strongly. 

Repairing Mackintosh.— If the water penetrates 
the mackintosh in a few places only, obtain from a 
rubber warehouse some rubber cloth in tlie piece as 
near like the coat as possible ; also get some rubber 
solution. Cut the rubber into circles large enough 
to cover the leaks, spread the rubber solution upon 
them, and also upon the mackintosh inside wherever a 
leak occurs, and press the circles of rubber into place. 
Press under a weight for a day or two. The mackintosh 
should be thoroughly dry before being treated. 



50 



Cyclopaedia of Mechanics. 



Boots Cracking Across the Toes.— All boots, and 
more especially m-fltting boots, have a tendency to 
crease and crack across the toes, and to counteract 
this tendency the following precautions should he 
obserred. Patent leather boots should always be 
rubbed down across the joint over the toes while the 
foot is slightly bent, the rubbing being done with the 
hand or with a piece of soft rag. If the weather is at all 
cold, the boots sliould be warmed in front of the fire before 
they are put on, and then rubbed. Calf leather boots 
should always be carefully treed up when cleaning them, 
and each time the boots are worn the creases should be 
taken out by rubbing with a bone. 

Moulds for Casting Brass.- In making moulds for 
fine brasswork, ordinary sand should be mixed with 
loam, which is a more clayey sand. The mould must 
be well dried before a fire, and then dusted with 
very iiue charcoal powder. If a very delicate surface 
is desired, it could be smoked over with a pitch torch. 
This method is more troublesome, biit the results are 
excellent. The patterns must be inserted after the 
smoking, and the two faces brought together again. The 
soot from the smoking will gire a perfectly smooth 
surface, and the castings will come out clear and sharp. 

Testing a Try-sq.uare.— Below is given a method of 
testing a carpenter's square. Shoot the edge of a 
piece of board quite straight, apply the sciuare as 
shown at A (Fig. 1), and draw a line ; then turn 



V 



mixture the most varying tints can be produced. The 
purest and best of these colours should be used ; then 
only a little colour will be necessary. Straw hat 
varnish making is throughout a cold process, only 
careful intermixing, slow digestion to complete the 
solution, stirring from time to time, and perhaps flltra. 
tion, being necessary. To the above stock varnish add, 
to obtain black, 55 grammes of spirit-soluble ivory black 
ler 9 litres of varnish i the shade may be varied beauti- 
uUy by a slight addition of spirit blue or malachite 
green. For oiive brown, add 15 grammes of brilliant 
green, 55 grammes of Bismarck brown, and 8 grammes 
of spirit blue. For olive green, add 28 grammes of 
brilliant green and 28 grammes of Bismarck brown. 
For nut brown, add 55 grammes of Bismarck brown and 
15 grammes of nicrosine. For . mahogany brown, add 
23 grammes of Bigmarok brown: the colour may be 
deepened by a little nicrosine. For peacock blue, add 
55 grammes of spirit blue and 28 grammes of induline. 
The above are mostly dark coloured varnishes, for the 
preparation of which shellac is only suitable. Some 
lighter coloured solutions will now be given. A white 
stock varnish suitable for the prepai-ation of light- 
coloured straw hat varnish is a solution of 27 grammes 
of sandaraoh, 9 grammes of elemi-resin, 9 grammes of 
pine resin, and 2J grammes of castor oil in 18 centilitres 
of methylio alcohol. To produce a golden yellow 
colour, add to 9 litres of this varnish 55 grammes 
of ohiTsoidine and 55 grammes of anUine yellow. 
For pale green, add 55 grammes of brilliant green 





Fig, I 



Fig. 2 



Testing a Try-sq[uare. 



the square as at B, and if it is true the blade should 
fit the Une; it it is less than a right angle it will 
be as shown at CD (Fig. 2), and if more than a right 
angle the defect will be as indicated at El? (Fig. 2). If 
the blade has moved or has been knocked out of truth 
through a fall, it should be knocked back into its proper 
position and, when true, the rivets should be tightened 
by careful hammering. If the blade is quite fast in the 
stock, but untrue, it must be filed true to the stock. 

Prevention of Nodules on Electrotypes.— Warty 

nodules on the edges of electrotypes are usually 
caused by the employment of small currents. This 
may happen by using a small cell or small elements 
in the cell, or by the employment of connecting 
wires having a high resistance. It is unusual to find 
these nodules on edges protected with paraffin, and 
their existence points to a soiling of the parts whilst 
blackleading the mould. When these nodules are 
troublesome, it is usual to take out the moulds, out or 
file off the warts, give the copper a dip in nitric acid to 
clean it, then re-immerse the electrotype, and proceed 
with the deposition. 

Coloured Varnishes for Stra\r Hats. — All straw 
hat varnishes are required to dry in a few minutes 
and form a firm, pliant, and elastic cover, though a 
high lustre is not essential. Hence spirit varnish is 
particularly suitable ; any desired colour is gained by 
the addition of pigments soluble in alcohol, the coal 
tar (aniline) colours being best adapted lor this pur- 
pose. Generally, the manufacturer of straw hat varnish 
prepares two or three colourless stock varnishes which 
may be coloured as occasion requires. Shellac is 
the indispensable gum tor every spirit varnish, but it 
cannot, owing to its brown colour, furnish a white or 
pale varnish, so it is suitable only for dark coloured 
varnish. A good stock varnish from which black, 
brown, dark green, deep blue, and similar tones 
may be made is obtained from 180 grammes of 
shellac, 45 grammes of soft Manila copal, 45 grammes of 
sandarach or resin, 1 gramme of castor oil, andsufflcient 
methylic alcohol to form a suitable solution. To pro- 
duce coloured varnishes from this the respective alcohol 
soluble auiline colour alone need be added. Ivory 
black, spirit blue, Bismarck brown, aniline yellow, 
brilliant green, safranine, and crystal scarlet are among 
the colours suitable lor this purpose, and by their 



and 7 grammes of aniline yellow. For medium bine, 
add 55 grammes of spirit blue. For deep blue, add 
55 grammes of spirit blue and 55 grammes of 
induline. Vary the proportions of these two pigments 
to obtain other blue tones. For peacock blue, add 6'5 
grammes of spirit blue, 28 grammes of induline, and a 
little brilliant green. For violet, add 28 grammes of 
methyl violet. For crimson, add 55 grammes of safra- 
nine. For chestnut brown, add 55 grammes of safranine 
and 15 grammes of induline. 

Melting Silver in an Open Fire.— Procure a small 
fireclay crucible in which to melt the silver. For a 
flux use equal quantities of finely powdered charcoal 
and sal-ammoniac. Make up a large, bright coal fire 
in an open grate, and when the fire is quite clear 
break a hollow space in the centre. In this space 
place the crucible, and allow it to get red hot; then 
put in the silver, and draw some of the hot coals closety 
around and over it. Blow the fire with the bellows until 
the crucible gets white hot, when the silver will melt, 
the fusing point being at 18/3" F. (1022-7° C). Then 
add the aux to clear the surface from scum. Again 
make the crucible hot, and quickly pour the contents 
into an iron ingot mould previously made" scalding hot. 
One or two ounces of silver may be melted at a time in 
this way. The fiux may be stirred with a pointed rod of 
iron previously made red hot. 

Particulars of Rectilinear Photographic lens.-- 

The word rectilinear simply means "right lines,' 
and is a name applied to lenses which do not distort 
straight lines when such fall near the margins of the 
plate. Such lenses represent a square as a square, and 
not like a pin-cushion or a barrel, as is the case with 
'a single lens when the stop is placed respectively behind 
or before the lens. Consequently, rectilinear lenses are 
doublets— that is, they have a lens at each end of a tube, 
with the stop between, thus introducing both kinds of 
distortion, the one nullifying the other. 

Cleaning W.C. Basins.- To clean w.c. basins apply 
spirit of salts by means of a piece of old rag tied 
to the end of a stick, and after sufficient time has 
elapsed for the incrustation to become softened, 
or partially dissolved, wash with clean water. If the 
incrustation is very thick, the operation can be hastened 
by scraping. Any spare acid should be thrown down 
the drains, as it is a dangerous poison. 



Cyclopaedia of Mechanics. 



51 



Making Brass Gas-cocks.— Here are given full In- 
fitructions on casting and finishing Bmall trass gas- 
oocJss. The patterns may be of wood or brass, but 
■brass is to be preferred, as it wears much better 
than wood. Core prints must be turned on the ends 
of the patterns so that, when moulded, places wUl 
be left m the mould in which to insert the core. The 
patterns must be made aufaciently large to allow for 
Bhrinkage and for the metal turned off in finishing. The 
ends of the core patterns must be exactly the same size 
as the core print on the brass pattern. Core stocks for 
each of the cores must be made. The keys may be 
made in the same manner as the body of the casting. 
Figs. 1 to 4 give views of the body of the cook and the key 
in two positions. The key must be sufficiently large to 
™?'i^°''°.,',°/ gi'inding. Make the moulds, trim taem, 
and they wiU be ready tor finishing. In finishlngthe cock, 
use an iron bell chuck or an ordinary brass-turner's chuck. 
Turnoneend of the cock square, and thread the hole with 
a suitable sized thread. Kepeat the operation at the other 
end of the cook. Skim the cook all over, and face both 
■ends pt the keyway. Then turn the hole for the key 
slightly taper as cast. Now skim the outside of the key 
casting on the taper similar to that of the hole In the 
■cook, and press thfe cook on. If it does not go on as it 
should, skim a little more tUl it is correct. Square the 
end oft, drill a hole up it, and thread with a screw to 
carry the small bi-ass screw that holds on the D washer, 
to prevent the tap being puUed off and to obviate the 




Making Brass Gas-cocks. 

«aoape of gas. Each tap must be turned to each cook, 
and must be left in it till ground ; this will save time 
and waste. In grinding in, fix the tap in the chuck, place 
a little loam and water on it, and press on the cock. This 
will cause the loam to grind down the surface of the k6.v 
a.nd make a good joint. The common test applied by the 
workman is to draw out all air by the tongue and mouth, 
when the cook will, if sound, adhere to the tongue. The 
key must have a round hole drilled through it, and at 
the top should be inserted a pin, which catches on the 
■top of the cook and prevents its being turned more than 
halfway round. In making the sand core, insert a piece 
■of thin iron wire through lengthwise ; this will 
strengthen the core (see Fig. 4). The cores in each case 
must be made to suit the purpose, and will depend on 
the size and nature ot the cook in hand. 

Making Hand-cart for Carrying Furniture.— The 

cart here described is 6 ft. long by 4ft. 6 in. wide, and 
may be used for carrying furniture. As the wheels 
are to run underneath the bed of the cart, the distance 
between the springs must be less than is customary 
in ordinary work. Set out a full-size plan ot the cart, 
mark in the position ot the wheels, -so that the stock 
hoop does not project beyond the side of the cart, 
and mark in the position of the springs or stays to 
which the axle is fixed, as summers have to be framed in 
to Sx these to. For the outside framing, two rails 2 in. 
wide by If in. deep, front and hind bars 2 in. wide by 
2i in. deep, are framed together squai-e and true, and flush 
on top. This framing is boxed out on the top inner edge, 
i in. on by i in. deep, to take the boards to form the floor. 
At such a distance in from the outside as the springs will 
come, frame in two summers 2i in. wide, thick enough to 
be level with the boxing out on top, and flush with the 
•cross-bars at the bottom. If the oart is to have two 
handles, these are bolted to the summers ; if there is to 
be only one handle, it is fixed in the centre underneath 
the bottom to both the hind and front bars. Ifext bolt 
on the springs or stays ; if springs are used, see that the 
■scroll irons and springs combined are of such a de^th 
that the wheel is Si in. clear at the top to the under side 
•of the frame j if iron stays are used, lin. clearance will 



suffice. Having bored on the springs and fixed the axle, 
])ut in the bottom boards of red deal lin. thick, the 
grain of which should run from side to side. To protect 
the outer corners ot the frame, iron oornjer-plates should 
be fixed round, about 6 in. each way. The wheels should 
beabout 2ft. 9in. high; this would bring the top of the 
cart about 3 ft. 3 in. from the ground line. To make the 
cart more useful, portable boards may be fitted round 
by placing small iron staples on the outside of the frame, 
and irons on the boards, the irons being so made as to 
slip into the staples. 

Why the Welabach Mantle gives light.- The tem. 
perature of the incandescent bodies with which a 
welsbaoh mantle is Impregnated may be assumed as 
being about 3500° P. The quality of the light depends 
to a certain extent on the amount of air admitted, 
which should be just sufficient to ensure combus- 
tion ot the gas ; the burners employed are constructed 
on this principle. The quality ot the light in an incan- 
descent burner depends on the raising of the finely 
divided rare earths (thorla, ceria, etc.) to the highest 
degree of incandescence by the agency of a Bunsen 
burner, which is constructed in such a manner that the 
amount of air and gas supplied to the burner are in the 
proportion which will yield a non-luminous flame and 
give out sufficient heat to effect the object required. 

Stereoscope for Holding a Number of Views.- A 

simple effective stereoscope for exhibiting a large 
number of views is shown in the accompanying sketch. 
The apparatus consists of a box A with sliding adjust- 
ment along a wood strip B similar to the usual form 




Stereoscope for Holding a Number of Vieira. 

of cheap stereoscope. At the back of the box at 
are two spiral springs which sink into a recess. By 
these springs the front picture is kept in position, what- 
ever number ot views the box may contain. Across the 
front ot the box is a rod D worked by a handle E. "With 
this rod turn two rubber-tyred wheels ]?, one on each 
side. To use the apparatus, the box is filled with pictures 
(which should be pasted on thin mounts), and the 
focus is adjusted for the front picture, wliioh is removed 
as soon as it is done with by 'turning the handle in the 
direction indicated, when the wheels ]? drag the picture 
out of the way and it falls into the top. The next picture, 
pressed forward by the spring, is already in position. 
This apparatus might easily be constructed in pedestal 
form u the focal adjustment is effected by means of a 
long screw with a handle and a nut in the bottom ot the 
box. The changing handle would, of course, be fixed 
outside by lengthening the rod B. 

Depositing Nickel on Wax Moulds.— Before nickel 
can be deposited on a wax mould so as to get a smooth 
sheet it is necessary to prepare the mould with black- 
lead or with bronze powder as for the electrotype pro- 
cess, and first deposit on it a thin film of copper in an 
electrotype solution. If the object desired is a copy of 
a design impressed on the face of the mould, it wul be 
advisable to remove the mould to the nickel vat when it 
has become coated with a very thin film ot copper, and 
deposit the nickel on this film. If the design is not 
undercut, it may be possible to peel off the film ot copper 
from the nickel ; but some difficulty may be experienced 
in getting a deposit ot nickel thick enough to form a 
plate or sheet, as thick deposits have a tendency to crack, 
curl up, and peel off. To get a tough coat, the nickel 
should be deposited slowly with a low-tension current. 

Cutting the Top off a Stoneivare Jar.— In cutting 
the top off a stoneware pickle jar, first make an ink 
mark right round the jar at the place where it is 
to be cut; then with a new triangular file wetted 
with turpentine make a mark over the ink mark, 
cutting through the glaze. Enlarge the file mark with a 
rasp; lubricating with turpentine. It is better to cut 
through the jar with the rasp, but as this process is 
very tedious, after cutting halfway through stand the 
jar in water up to the flle mark, and with a chisel and 
hammer tap on the file mark until the top comes off. 



52 



Cyclopsedia of Mechanics. 



Making Rubber Solution, — With a sharp knife 
wetted, cut into thin slices 1 oz. of pure Para rubber. 
Place it in a wide-mouthed bottle, cover It with carbon 
bisulphide or benzene (coal-tar naphtha), and cork 
down. Next day the rubber will have swollen con- 
siderably and have absorbed most of the liquid ; pour 
on more liciuid, and continue the addition until a thick 
fluid is obtained. One ounce of rubber will make about 
Ipt. of solution, which is used asa oementforrubber goods. 

Making a Safety Guard for a Circular Saw.— The 
liability to accident by timber being thrown from the 
circular saw has necessitated the provision of safety 
guards. The guard about to be described is simiDle in eon- 
Btructlon, elEcient, and comparatively Inexpensive. Pig. 1 
of the accompanying illustrations shows a saw bench with 
a suitable guard fixed in position ; A is the bench, B the 
saw, c the fence, D a pillar, E radial arm, P the guard 
hung to the arm and secured by means of a small pin 
G. The radial arm is held in position by means of a set- 
screw H. By easing this screw the guard may be turned 
hack out oil the way while screws are being changed, or 
while a saw is being topped in the bench. Immediately 
underneath the socket of the radial arm there is a collar 
washer J, which is also held in place by means of a set- 
screw K. The advantage of this washer is that when the 



radial arm, thus securing the guard to the arm. Hole* 
should also be drilled at the ends to secure the piece to 
the guard by means of small rivets or bolts, shown at Q 
(Fig. 1) , passed through holes in the guard and riveted, or 
the nuts screwed up tightly, as the case may be. A 
piece of wood Hn. or iin. Jihick is now shaped as shown 
at E (Fig. 1) ; the bent piece of iron or guard is screwed 
to this. This piece of wood not only protects the saw 
but also makes the guard more rigid. The guard is now 
completed, and when shifting guards, all that has to be 
done is to withdraw the pin G, place the other guard on 
the arm, and insert the pin lower, or raise the guard, as 
the case may be, to suit the diameter of saw or depth of 
piece that is being sawn. 

Turned Wood Case for a Drum Clock,— The useful 

and ornamental clock case illustrated below is in 
three separate mouldings A, B, C, and is thus much 
easier to turn than if It were all in one piece. It can 
be made in satin walnut, mahogany, oak, etc., but 
the first is very easy to work, cheap, and, when polished, 
looks well. Start with the moulding marked A, the 




set-screw that secures the radial arm is eased, the washer 
prevents the socket of the arm from sliding down the 
pillar. If there were ho washer, the left hand would 
have to be used tor holding the arm so as to prevent it 
eliding down the pillar, when the guard would drop on 
to the saw. L indicates a piece of timber partly cut by 
the sitw. It will' be seen that the guard does not come 
dowj) on to the piece that is being sawn. The sawder is 
therefore able to see the tooth m the cut. This is an 
important point ; for if nothing can be seen of the teeth 
or cut (a,K is the case with some guards), it is impossible 
for the sawyer to see whether the saw is making a true 
course or not. It will also be seen that this guard may 
be raised or lowered to suit timber of different depths. 
There should be two or three guards of different sizes 
for saws of various diameters. The same radial arm will 
answer for all the guards. The iron pillar D (Fig. 1, and 
illusti'ated by Fig. 2) should be of suitable length, and 
about li in. in diameter. At M there is a 'shoulder that 
rests square on the top of the table. The part N is 
square, and there is a cotter- way Oto receive a small 
cotter. Near the outer edge of the table a square hole is 
made by first boring a hole and then filing it square. 
The square part N of the pillar should fit nicely in this 
hole. A cotter is then driven in the cotter-way, which 
holds the pill.ir firmly in position. The square prevents 
the pillar from turning m anj^ direction. The guard 
P (Fig. 1) is a piece of wrought iron about IJin. wide by 
Ain. thick, and of suitable length, and drilled to receive 
the necessary screws and rivets, or small bolts with nuts 
(see Pig. 1). This piece of iron is bent to the required 
curve. A piece of iron is now made to the shape 
shown at P (Fig. 1), or any convenient shape. A hole is 
made at the centre to receive the radial arm E, and 
another hole drilled at the top down through the centre 
to receive a pin that passes down through it and the 



Turned Wood Case for a Drum Clock, 

wood for which should be liin. thick. The back is first 
planed or turned flat, and the block is then placed on 
the screw chuck and the outside turned and finished 
with glasspaper. Then with pencil or compasses strike- 
a circle 6J in. in diameter and cut right through on the- 
llne with a thin parting tool ; this inside piece will thea 
be large enough for the top moulding 0. The middle 
moulding B should be made in the same way. For th& 
top moulding turn and finish the outside, and bore- 
to 3Jin. for the inside lip at D, T*, in. long. Then place the- 
moulding in a hollow chuck and bore it out to ifa in. by 
i^m. deep. The sizes given are for the globe drum clocks, 
costing a shilling or so each. Of course, the inside 
measurements must be varied according to the size of 
clock to be fitted. The three mouldings are glued 
together, three screws 14 in. long being put through A . 
into B, and three through B into C. Unscrew the ring 
and legs from the clock, and drive soft wood pegs in 
place to keep the works from slipping. A ring E, which 
just overlaps the edge of the clock and fills the space, is 
not glued in but is held in position by three screws, so 
that the clock can be removed at any time if required 
for repairs, etc. A brass plate screwed on the back tor 
hanging the clock completes the case. 

Black Streaks in Nickel-plating.— Black streaks in 
deposits of nickel are caused by bubbles of hydrogen 
gas, which form in clusters on the surfaces of articles- 
and then burst. They may be prevented by gently 
agitating the articles whilst being plated, or by stroking 
the clusters with a stout feather and thus bursting them- 



Cyclopaedia of Mechanics. 



53 



They appear frequently when nickel solutions have not 
been agitated tor some time, and have consequently 
settled in a stratified condition. It is therefore advisable 
to stir the solutions occasionally in the evenings, and 
thus thoroughly mix the contents. 

Fitting a Watch Hairspring.— In applying a new 
hairspring to a watch, the centre coils are broken 
out, about a quarter of a turn at a time, until there 
is room for the collet. The effect of this upon the 
time of the watch can he neglected, as the actual 
length of spring removed is so small. Now bend a 
small length sharply inwards for pinning into the collet.- 
Place the collet, right way up, on a broach, and push It 
on tightly ; hold the broach in the left hand, pass the 
hairspring down the broach, and with the tweezers in 
the right hand, insert the end of the spring into the hole 
in the collet. Lay the broach down, with the collet and 
spring on, and file up a brass pin to fit. Then fix it in 
and break off the pin, which should previously be half 
cut through with a pocket-knife. 

Mounting Stereoscopic Photographs.— It is some- 
times the case when viewing mounted stereoscopic 
prints that the objects in the background, when seen 
through the stereoscope, appear in front of the picture. 
The cause of this^may be gathered from a consideration 
of the following principles. Let A B (Fig. 1) represent 
a pyramid and C the lens-board of a camera, with 
lenses D and G forming Inverted images E and L on 
the plate P. Supposing the operator to be standing 
behind the plate, the image formed by D at B will be 
similar to that seen by the right eye, and the image 
formed by G at L similar to that seen by the left eye. 
Now if a print be taken from this negative by placing a 
6heet of sensitive paper against the Sim it will be like 




mounting Stereoscopic 
Photographs. 



copper sulphate crystals in hot rain water untU the 
water is saturated with copper, and will not dissolve any 
more. Allow this to get cold, then add 4 fluid ounces of 
sulphuric acid to each gallon of solution. Use anode 
plates of pure copper connected to the copper elements 
of the battery. Work the solution cold with current 
from two Daniell cells of i-gal. capacity. Connect the 
cells in series (copper of one to zinc of next) to start 
the deposit, and when the boat is covered with a thin 
film of copper connect the ceUs in parallel to finish. 

Cutting Shoe Finishers' Irons.— Irons tor ironing 
np the edges of boots and shoes are of various forms, 
a few of which are shown in the illustrations. They 
will serve as examples of how irons should be made 
and recut. The iron is of such importance to the 
finishing of all classes of work that it is worth while 
to learn how to cut kit, as it is called, especially 
by those who are at a distance from any large town. 
It new irons are to be made, stocks for them must 
be procured ; these stocks are oblong pieces of squared 
iron, which are ultimately shaped as shown in figs. 
1, 2, 3, and i, each iron having a stem at the bottom 
that can be driven into a handle. The better way, 
however, is to buy the irons already shaped, as they 
are rery cheap, and then a careful reoutting produces a 
good iron. Stocks for some of the smaller irons can be 
made from the butt or shank ends of files or rasps. A 
small vice and the necessaiT flies are the tools required. 
Pig. 1, in which the crease or indentation B produces a 
bead on the edge of the sole, can be made like all irons 
of that kind, single and double, In sets in various sizes. 
The same remark applies to Pig. 2, but in the latter an 
indentation or crease is thrown upon the welt side. 
If these two irons are combined in one, the crease at 
Fig. 1 being placed at C in Fig. 2, a double iron is pro- 
duced, and a set of such irons would be very useful. 
They can run up to almost any size, by widening the 



f=^ 



(ty\ f^=^ 




■Rg, 3 

Shoe Finishers' Irons. 



Pig. 2— that Is, the left-hand view as seen by the left eye 
will now be on the right, because the images have heen 
turned the right way up. Practically, the reason 
why the distant objects come forward is that 
the right eye is looking at the left eye view, 
and vice versa, owing to the two views not having 
been transposed in mounting. In mounting stereo- 
scopic prints, to prevent confusion, lay them face 
down, and run a short line across the back of the paper 
where the two prints join (see Fig. 2). Trim straight 
across the two prints for the base line and for the 
top. Now cut the prints in halt and trim to about 2| in. 
square, leaving on the right of the right-hand print tin. 
more of the picture than appears on the left-hand print, 
and on the left of the left-hand print i in. more of the 
picture than appears on the right-hand print. Now 
mount the prints about Jin. apart, with the half-lines on 
the outside of the print instead of being joined as they 
were before the print was cut. 

Cubing Round Timber.— The easiest way of measur- 
ing . round timber, to get the solid contents, is to 
take one-fourth of the middle girth of the timber in 
inches, square this dimension, multiply by the length in 
feet, and divide by 144 s the result is the reputed cubic 
contents. If the bark is on, make an allowance tor it by 
deducting 1 in. per foot from the actual girth before 
dividing by 4. Example : Round log of oak 20 ft. long, 
18 in. diameter one end and 12in.the other, girth 48 in. 
Then 48 in. = 4ft., lin. per foot = 4in., and48-4 = 44in. ; 
quarter girth = 11 in., 11 squared = 11 x II = 121, 

and 121 X 20 = 2,420. Then ?;^= 16-8, say 17 cub. ft. 
144 

Copper'platlng Model Boat.— Instructions are here 
given on copper-plating a boat made partly of metal and 
partly of wood. First well soak the woodwork of the boat 
in linseed oil to close all the pores and prevent the copper 
solution penetrating the wood ; then expose it to the air 
for a day or two to oxidise and harden the oil. The part 
to be coppered must now be coated with blacklead, weU 
brushed in and polished. On this coating the copper 
will be deposited, therefore the connecting wires must 
be in close contact with it at several points. Dissolve 



space between O and p (Pig. 2) from Jin. upwards, 
increasing the space by V, in. for each size. Fig. 3 ia 
somewhat like Fig. 1, but with a slightly flatter top. It 
shows a double pump iron, which is made to flt two 
thicknesses of edges ; It is, in fact, two irons in one, and 
being larger than one iron only, it retains heat tor a 
longer time. In Pi^. 4 the curve marked P can be modi- 
fled as required ; being a waist iron, it is used to set up 
edges of all kinds, some of which are thin and square, 
others round, and others of various angles. The files 
can be bought in sets ; they are called kit files, and can 
be obtained probably at almost any leather grindery 
stores. These' files consist of a four-cornered file, a flat 
four-sided bastard file, a tapered file, a knife-shaped file, 
a small rat-tail file, and a triangular file. Jewellers' 
files of various shapes may also be used, and they 
come in vei-y handy tor cutting different fancy shapes. 
The rough cutting can be done with coarse files, and 
the finishing of the shaping process with finer fUes, a 
last touch being given with fine kit files. "When the 
proper shape has been obtained the creases can be cut, 
or the beads squared up with the tapered file, the 
knife-shaped file, and the small rat-tail file, and the 
square beads finished with the triangular file. So tar, 
the iron has only been shaped up and roughly finished 
as far as files can do it; the final finishing and 
polishing are done with emery powder. Coarse, medium, 
and flour emery are mixed with oH, the paste heing 
smeared on pieces of leather and the iron rubbed 
upon it; the coarse emery is followed by the medium 
and then by the flour emery, the finishing being done 
with dry flour emery. If the iron is for setting up a 
stout edge, several pieces of leather are nailed together, 
and the emery smeared on the topmobt one. During 
the filing operations the greatest care must be taken 
not to wear away the creases and beads. 

Fireproofing Theatre Scenery.— In 3 gal. of water 
dissolve 1 lb. of alum. With a stock brush thoroughly 
soak the stretched canvas curtains or other fabric, 
leaving no part unbrushed. When thoroughly dry, 
prime in for painting. Another solution consists or 
10 per cent, sodium tungstate. Apply as above, and 
when dry prime in. 



64 



Cyclopaedia of Mechanics. 



Ghost Illusion for Amateur Theatricals. — Pnlut 
ou canTas a scene representing a room or library, 
and showing a taooltcase. Tiie part of the hookoase 
that would contain the shelves and books must be 
out out of the canvas, the framework only being left, 
and this framework must be so painted as to have asolid, 
substantial appearance. The canvas that has been cut 
out must be replaced by a black net or gauze, and the 
shelves and books must be painted on the gauze, so that 
when lighted up from the front the bookcase will ap- 
pear complete. Behind the ^uze and close to it the 
movable oat cloth is hung. This is a piece of canvas 
dead black in colour, 12 in. larger all round than the cut- 
out portion of the bookcase. The ghost or vision stands 
behind the cat cloth. The light Is now turned down in 
the scene so that the room is darkened, and at the same 
time a good light is turned on at the back, and is so 
arranged that it falls ou the front of the figure either 
from the left- or from the right-hand side. While 
darkening the scene and turning up the lights behind 
the cat ototh must be pulled up or drawn on one side, 
and the ghost scene is complete. With judicious manage- 
ment this will answer for tableaux by adding accessories 
on a large or small scale as may be necessary. 

A Simple Sledge. — The accompanying illustration 
shows a sledge for two persons ; it can, however, be 
shortened to accommodate one person only. It is 5 ft. 
long, 1ft. Sin. wide, and 1ft. 4Jin. deep, and should 
be made of red wood, being afterwards painted. The 
sides A are mortised to receive three rails B, whjoh bind 
them together ; the rails are Sin. broad. . The sides C of 
the seats are dowelled to the long rails or runners A, 
and the seats D are nailed down. To stiffen the seats 
and frame, iron bands should be inserted, one below 
each seat, each being long enough to allow a screw 
to be inserted in the runner. A half-round iron strap 
is carried along the under edge of the runner, and 



dull surface for the next coat, as if two coats were 
put on without flatting the top coat would "oiss" up 
and spoil it. If only one coat of japan is given, 
the carriage, etc., will now be ready for lining out ; for 
this, camel- or sable-hair pencils, called flne-Uners, and 
picking-out pencUs are used. The colour (vermilion) 
should be mixed in a^small dipper with gold size or 
varnish to a creamy thickness. Another small pot 
contains clear turps. The pencil is dipped into the 
turps, then into the colour, and worked up on the 
palette ; then, holding the pencil between the fore- 
tinger and thumb, and using the other fingers as guides, 
line out as required. When dry. well clean the whole 
with a sponge, and give the underworks and wheels a 
light coat of carriage varnish, and the body a coat of 
under-ooatlng body varnish. After standing two days, 
well flat the whole as the japan was done, being careful 
to get out every particle of pumice dust from the corners 
and crevices, using water freely ; then thoroughly dry 
off, and give the body a good full coat of finishing body 
varnish, and the under carriage, etc., a coat of pale 
carriage vamish, putting satficient on to obtain a good 
finish without getting runs. To make a successful job, 
the carriage should be done In a light, roomy place, free 
from draughts, and kept at a temperature of about 75° F. 

Stump Moulding.— The following supplements the 
information on stump moulding given on p. 36. Stump 
moulding is so called because the moulder works on 
a small bench called a " stump." The box parts used 
are about 18 in. square and Sin, deep. The best are 
of mahogany or other hard wood to combine lightness 
and strength; they are hinged at one corner, and 
have a fastening at the opposite corner, as at A in the 
accompanying Ulustratiou. The hinges and fittings 




A Simple Sledge. 

curled round in the front to form a loop, as at E, to 
which may be attached the hauling ropes. The follow. 
Ing is the quantity of stuff required. Two pieces, 5 ft. 
by 4i4 in. by |in. ; three pieces, 1 ft. 5 in. by S in. by i in. ; 
four pieces, 11 in. by 9 in. by Jin.; and two pieces, 1ft. 
6iin. by 10 in. by ^in. The following are the positions of 
the rails and seats. From the nose of the sledge to the 
first rail is (i in. ; from the inside edge of this rail to the 
front of the seat is 7in. ; the centre rail is Immediately 
in the centre of the sledge, and the second seat 7 in. 
from this rail j the back rail is 6 in, from the end. 

Painting and Varnishing a Fhaeton.— It is supposed 
that a phaeton is to be repainted black and picked out in 
red, and then varnished. If the paint is cracked very 
much, the best plan will be to remove it by means of a gas 
jet or burning lamp and an old plane-iron. The vehicle 
may then be filled up and painted. If the paint has only 
cracked through the varnish, rub it down to the colour 
with pumice stone and water, then clean off thoroughly 
and give a coat of colour made of tub white lead and a 
small portion of driers and iarnpblack, mixed stiff, with 
raw linseed oil and thinned down with turps; this 
should dry in about ten hours, but should be allowed 
to stand a day longer to get hard. In the meantime the 
wheels, under caiTiage, etc., should be well rubbed down 
with glasspaper, and a coat of lead colour applied as 
above. Any holes or dents in the body should now be 
filled with a stopper made of dry white lead, gold size, 
■ind black japan, beaten up stiff with a mallet or hammer ; 
and the wheels, carriage, and shafts puttied up where 
required, and afterwards lightly sandpapered olf. The 
body, when the stopper is hard, is faced over very lightly 
with pumice stone and waterto take outthe brush marks 
in the lead colour, after which the whole is given a coat 
of ground drop black, thinned with turps and varnish: 
this should dry in about four hours. Then add a good 
drop of black japan to some of the dead black pre- 
viously used, and give another coat ; let this stand for a 
day, then give a good hard sponging off, ready for the 
first coat of japan. If the work is to be finished in a 
first-class manner, a second coat of japan is necessary i 
but before applying this the first coat must be flatted 
down with pumice dust and water on a pad of cloth to 
remove any nibs which may exist, and to make a 



Box for Stump Moulding. 

may be of brass. The other two corners of the box are 
dovetailed together. The box parts are fitted together in 
pairs, the bottom part being made to take the pegs B. 
The" moulder takes the bottom part, brings the ends A 
together, and secures them. He rams it up on a 
pattern plate or an oddside, audthen rams the other box 
with the top part ou the other side of the pattern plate 
or the other oddside. The two box parts are then put 
together and moved off the bSnoh or stump to the floor. 
The corner A is unfastened, and the box parts are opened 
and removed, leaving the sand mould on the floor ready 
for pouring in the iron. It will be seen that only one 
pair of box parts will be required to make any quantity 
of moulds on this principle. Of course, this method is 
only suitable for use in casting comparatively small 
articles such as cast heel-tips for boots. 

Colouring Gold.— The foUowiug pickle has been found 
very satisfactory for imparting a rich colour to gold 
rings, scarf-pins, etc. Alum (powdered) 1 oz., common salt 
loz., saltpetre 2oz., and water 10 oz. Wash the article 
to be coloured in warm water to which a few drops (say 
fifteen to twenty drops to a breakfast-cup full of water) 
of ammonia have been added, using a soft brush and 
soap. Einse in cold water, and dry in hot sawdust. Then 
immerse the article in the pickle for about two minutes, 
and again dry in hot sawdust. Finally polish with rouge. 

Hints on the Use of a Kodak.— The ordinary pocket 
kodak takes pictures 2 in. by liin., and the folding 
and newer kodak takes pictures 3Un. by 2iin. When 
closed, the folding kodak measures only H In. In thick- 
ness. These cameras, having a fixed focus (that is, 
allowing of no adjustment of the focus for near 
objects at different distances), are unsuitable tor any 
but fairly distant views, where the variation in focus 
is very considerably less than with near objects at vary- 
ing distances, because everything beyond a certain 
distance is more or less in focus. This result is obtained 
with a short focus lens and a small stop, but as the 
latter means long exposure, and as short ones are 
essential to good hand camera work, the fixed focus 
patterns cannot altogether be recommended. 



Cyclopaedia of Mechanics. 



55 



Portable Dog-beimel.— One-inch grooved and tongued 
l>oards 6 In. wide is a suitable material of which to 
make the portable dog-kennel illustrated by Fig. 1. The 
boards of the sides should be nailed to a li-in. by 
2-in. ledge at the top and a 3-in. by U-in. ledge at the 
bottom (see K and L, Fig. 2). The boards of the front 
and back should be nailed to similar ledges, as shown at 
E and P (Pig. 1). The boards forming each side of the 
roof should be naUed to the three bearers M, N, and 
(Fie. 2). Fig. 3 shows the construction of the floor. It 
will be seen that the kennel wiU be composed of sfeveu 
main pieces. A fillet about 14 in. by 1 j in. should be 
nailed to each end of the sides, as shown in the longi- 
tudinal section (Fig. 2) , anij also by the enlarged section 
(Fig. i) ; this is taken through A (Fig. 1). B (Fig. i) 



slsting of 1 part of nitrate of tin and 2 parts of chloride 
of gold dissolved in a little water and acid. Remove the 
article and wipe it with a clean linen rag. ' A slight 
excess of acid will increase the intensity of the black. 
The following method will also be found very good, and 
is the same as that adopted in oxidising silver articles. 
Give the article a light silver-plating by deposition, in 
a similar manner to ordinary cheap electro-plated goods. 
Then prepare a solution made as follows. Dissolve in 
a little acetic acid 2dwt. of sulphate of copper, Idwt. of 
nitrate of potash, and 2 dwt. of muriate of ammonia. 
After wai-ming the articles, apply the solution with a 
camel-haiT pencil or immerse in the bath, then expose 
them to the fumes of sulphur in a closed box. This may 
readUy be done by placing in a tin biscuit-box a red hot 




shows a portion of the boarding of the side with the 
angle flUet p nailed to it. The front and back can be 
fixed to the sides by eight 2i-in. by f-in. bolts and nuts, 
as shown at Figs. 1 and 2, and indicated by the section. 
Fig. i. Each half of the roof can be fixed to the ends by- 
eight bolts and nuts in a similar manner. The floor will 
rest on the ledges G and H (Fig. 2) round the bottom of 
the boarding. The roof should be covered with felt. 

Blackening Brass.— One method of blackening brass 
Is as follows. Dip the article in a bath consisting of 
1 part of sulphate of iron and 1 part of white arsenic 
dissolved in 12 parts of hydrochloric acid. When the 
article has become sufficiently black, rinse it well in 
several changes of cold water to remove the acid, dry 
in sawdust, and polish with blacklead ; it may then be 
lacquered with a pale lacquer. Another method, and 
one more generally adopted, although somewhat more 
expensive, is as follows. Well polish the article with 
tripoli, and afterwards wash it well in a mixture cou- 



FlG. 4 



Iron bowl, such as the bowl off a small lead ladle. In 
which are a few pieces of sulphur. Hang the articles 
on a rod across the tin, and close the lid. It will be 
necessary to do this where there is a fairly good.draught 
to carry oS the sulphur fumes. 

Tempering Gun Springs.— In tempering springs for 
guns and revolvers, make the springs red hot (be careful 
not to overheat them), then plunge them into cold 
water. Take them out, warm them over the Are, rub 
with suet, blaze them over a clear forge fire, and let them 
cool. The foregoing operation requires considerable 
practice to produce a desirable temper. 



56 



Cyclopsedia of Mechanics. 



Making Pipe-eye Scroll-irons.— Coaohsmiths' barrel 
heads of scroU-irous, or pipe-eye soroll-irons, are usually 
made as follows. For an ordinary sized one having 
an OTal stem, take a piece of square edge iron 1 in. by 
}iu. and ■well upset one end, making it rather wider 
than it is thick, setting it in slightly about It in. from 
the end to help in forming the eye, and round it off 
a little. Then make hot a piece of flat iron li in. 
liy iin. or Sin. thick, according to the width of pipe- 
eye required, and with the top and bottom fullers set 
it in to make a round bossi nearly cnt it through 
at the narrow pai-t with the gouge, and weld it on one 
side Of the ii-on already upset. Jffiake another boss, 
and repeat the weld for the other side, at the same 
time working the pipe-eye to shape and size, and working 
up the OTal close to the eye with the fiiller so as not to 
cut in, afterwards using top and bottom oval tools. 
When the eye is something like the desired shape, punch 
a small i-in. hole through the centre, gradually making 
the hole the required size with a steel mandril and work- 
ing up the round eye in top and bottom tools. 

Detachable Lath for Table Top. — The drawings 
herewith show a simple and effective arrangement for 
holding a lath to a table top. A cleat A (Figs. 1 and 2) 
is fixed to the end of the lath B by a couple of screws, 
as indicated, the Cleat and lath being held to the table 
top by inserting a wedge W, as shown. Fig. 3 is a view 



half turns; the time registered would be the same. 
The average good three-quarter-plate English lever 
watch, when lying down, has a balance arc ofabout one 
and a quarter to one and a half turns, and makes what 
are termed " long arcs." When hanging up It wUl make 
about a quarter of a turn less, say one turn to one and a 
quarter turns, on account of the greater friction at the 
balance pivots when in that position. The balance then 
rests upon the sides of the two pivots Instead of resting 
on the end of one, as in lying down. The watch then 
makes " short arcs. Obviously, if the short arcs are slow, 
the watch wiU go slower when worn in the pocket than 
when lying on the dressing table at night. But If the 
hairspring is Isochronous, causing the long and short 
arcs to be performed in equal times, there would be no 
difference in the timekeeping, whether th e watch was worn 
in the pocket or was kept lying down. Ordinary watches 
with hairsprings that have not been thus manipulated 
will lose about one minute per day in the pocket more 
than when lying down, the short arcs being then known 
as " sixty seconds slow." To test a watch for this error, 
set it on time by a regulator, noting its rate lying 
dial up for twenty-four hours. Then place it nine o'clock 
up for twelve hours and three o'clock up for twelve hours, 
and the sum of these two last positions will be its rate 
for the short arcs, while the first twenty-four hours' run 
wUl give its rate for the long arcs. 

Pattern for Saddle-sbapod Boiler.— A pattern for a 
saddle-shaped cast-iron boiler made as follows will 
answer for moulding in green sand. Prepare two 
substantial blocks A (Fig. 1) made to the inner con- 
tour of the casting. To these blocks nail or screw 
two pieces B and a piece C, all the pieces being made 




fta 2 "^^'FiQ 3 

Lath attached to Table Top. 



FIG. 2-. 
Pattern for Saddle-shaped Boiler. 



of the cleat ; this and the wedge should be made of hard- 
wood. 

Calculating Weight, etc., of Copper and Iron 
Wires. — In calculating the sectional areas of wires, 
the diameter in Inches corresponding to the number of 
the gauge of the wire must first be determined, and this 
can be got only from tables. Then to find the area of 
cross-section in square inches, square the diameter in 
inches (that is, multiply it by itself), and multiply by 
■7854. To find the weight in pounds of a single wire, 
multiply the cross-section, determined as just described, 
by the length in inches and by "28 for iron or hy '31 for 
copper. To determine approximately the weight in 

f>oundB of a stranded cable, multiply the weight of the 
ength of single wire by the number of wires in the 
strand. 

Timing of Watch Hairsprings.— The vibrations of 
a watch balance occupy exactly equal times (with 
an average hairspring) only when they are exactly 
equal in extent. For instance, in a watch with 
an ordinary flat hairspring, the balance vibrating 
exactly one whole turn, and going to time lying 
down, if the power be inorea.sed so as to make the 
vibrations of the balance one and a quarter turns, the 
watch will no longer be quite on time, but will either 
lose or gain— probably the latter. In such a case it 
may be said that the short arcs (one turn) are slower 
than the long arcs (one and a quarter turns) . But in the 
case of a breguet hairspring (with an overcoil), the 
spring can be so manipulated as to I'ender the long and 
short arcs of the balance isochronous— that is, performed 
in equal times. In such a watch it would not matter 
whether the balance vibrated one turn or one and a 



to the thickness of the metal j C should be saw-kerfed, 
80 that it will bend to the required curve. On each 
end of B and C fasten D, and two strips E, running 
the whole length of the pattern. Finally attach P by 
screws, which may be released to facilitate removal of 
the core, which is rammed inside the pattern. The 
pieces V should be stiffened by removable battens to 
prevent the ramming bulging the pieces outward. The. 
open part of the core is striokled to shape by a straight 
strip of wood G (Fig. 2) shouldered down to the thickness 
of the metal, and guided by and working between the 
two segments D (Fig. 1). When the mould is to be 
rammed, the battens used for stiffening the pieces P 
(Fig. 1) are removed. The inside of the pattern is then 
filled with sand and striokled off level with the convex 
edges of the segments. The latter is done with the flush 
edge of the strickle G (Fig. 2). After withdrawing the 
pattern, the stiffening blocks A (Fig. 1) are stopped off by 
nlling up the spaces left by them in the sand. The core 
niust be supported in the mould by studs or ohaplets, 
and provision must be made for securing the vent of 
the core through branches or openings on the casting. 
Any branch on the casting not occurring at the junction 
of the straight and curved parts of the metal should be 
left loose, so that it may be taken away on a draw-baok 
plate. Shallow bosses or facings should also be loose. 
All external edges of the casting should be well rounded. 
Fig. 3 shows the finished pattern. 

Coloured Cement Floor, — In making a coloured 
cement floor 2 parts of Portland cement by measure 
are mixed with 3 parts of sand. Before adding the 
water, mix with it a little red oxide of iron. The exact 
quantity of oxide to use will depend on the depth of 
colour required, and must be found by experiment. 



Cyclopaedia of Mechanics. 



57 



Particulars of Canada Balsam.— Canada balsam Is 
a sticky, yellowish-white material, with an odour some- 
what resembling turpentine. It is a crude turpentine, 
obtained by puncturing pine trees (Pinus canarienBis), 
and is similar to the other forms of crude turpentine 
obtained from Pinus sylvestris and Pinus maritima. 
On heating it, the Tolatile portion passes off, leaTing a 
bard reslu which is used as a waterproof cement for 
glass, etc., and for mounting specimens for the mioro- 
Boope ; for the latter purpose it is dissolved in chloroform. 

Brush for Enamel Paint.— A hog's-hair lather brush' 
tor which a barber has no further use is best for applying 
enamel paint. Having been constantly In hot water, 
the bristles are split fine so that no hair marks wUi be 
left when applying the enamel. Neither mops nor fitches 
are of any use ior the purpose •, the latter are employed in 
general painting for touching up, filling in, cutting in, 
and lining. A fitch can be softened in hot water. 

Setting-out tlie Bevel of a Hip Rafter.— Below is 
given a method of finding backing to hips. Set out 
■to scale the line of the pitch of the roof as shown at 
ABO (Fig. 1) , and a portion of the plan D E F G j EG will 
l)e the plan of the hip. At right angles to E G set up 
■O H, making it the same length as the height B C, then 




CIG. 1, 



S! H is the pitch of the hip. In E G take any point, as K, 
and at right angles to this line draw DP through K. 
With K as centre draw the arc LM tangent to EH as 
flhown, join ME, which is the angle of the backing. Set 
the bevel to the drawing as shown. Fig. 2 is a sketch 
showing the bevel being applied to the hip. A drawing 
as shown at Fig. 1 can be sketched on a board to about 
lin. scale on a building, and it will be found to take up 
much less time than the rule-of-thumb method of guess 
and trial. If work is to be done properly and without 
mistakes, time must be allowed to set it out. There is 
no other proper way. 

Be-tinniug Copper Vessels.— The object of tinning 
copper stewpans is to prevent chemical action on the' 
copper, which tnay be injurious to health. It also 
gives a much better appearance to copper cooking 
utensils, besides facilitating their being kept clean. 
To ensure success in re-tinning, the article must be 
perfectly free from grease or dirt— in fact. It must be 
chemically clean. For this purpose, first burn off all 
grease and dirt over a forge fire or witl^ a blow-pipe 
until the article is heated to a dull red colour, being 
particular where the handles are riveted on. Now wipe 
out the inside with a small pad of tow, and set down to 
cool, and when cold, thoroughly scour the inside with 
wet rough sand or powdered coke until it becomes clean 
and bright. If the dirt has eaten into the metal, or if 
the surface Is very black, wash it with raw spirit of 
salts (hydrochloric acid), using a piece of tow tied to the 
end of a short stick. Kinse with cold water, and then 
scour bright. When perfectly bright, wash the article 



well with cold water, taking care that no grit or sand re- 
mains inside, and then dust the inside with powdered sal- 
ammoniac. The outside must be prepared by coating it 
with a mixtui-e of salt and whiting; which should be of 
the consistency of cream ; this prevents any tin adhering 
to the outside. If the top of the outside requires to be 
tinned to the depth of about 1 in., as is the case with all 
new stewpans, it should be thoroughly cleaned as before 
explained. A band of tin 1 in. deep should be tightly 
heid round the top of the stewpan, while the mixture of 
salt and whiting is rubbed over the stewpan below the 
band. Now remove the band, and dust the bright sur- 
face of the stewpan, formerly covered with the tin band, 
with sal-ammoniac. A rubber, by which the molten tin 
is manipulated over the copper surface. Is made as 
follows. Coil the end of a piece of J-in. wire, about 
18 in. long, until it is about 2 in. in diameter, and tin 
the coil by soaking it in raw spirit of salts for some 
time, and then dipping it in a saturated solution of sal- 
ammoniac and killed spirit (chloride of zinc), and 
rubbing whilst hot on block tin or tinman's solder. Place 
thestewpanov ra forge fire, and in it drop a small quan- 
tity of pure Diock tin ; the amount of tin depends on the 
size of the vessel. The tin will soon melt, after which it 
must be rubbed over the copper with the rubber until the 
surface of the copper alloys with the tin. Any difiiculty 
in getting this result may be overcome by repeatedly and 
alternately dusting with powdered sal-ammoniac and 
vigorously rubbing over the tin with the rubber. The 
top of the outside of the pan may be more easily tinned 
with a soldering iron, the solution of sal-ammoniac and 
chloride of zinc .being used instead of the powdered 




Setting-out the Bevel of a Hip Rafter. 

sal-ammoniac. Care should be taken that the article 
is not allowed to, get too hot. The maximum heat is 
obtained when the molten tin can be rinsed round the 
inside of the article. The molten tin is then quickly 
emptied out into another pan, if more, than one is to be 
tinned, and the pan quickly wiped out with a pad of 
clean tow, which will remove any superfiuous tin, after 
which it must be suddenly plunged into a vessel of cold 
clean water, and then dried by rubbing with clean hot 
sawdust. When pouring molten tin from one pan into 
another, great care should be taken in seeing that the 
pan intb which it is to be poured is perfectly dry and 
warm, otherwise the possibility of the tin flying will 
make the operation highly dangerous. If a stewpan, 
ladle, spoon, or strainer requires to be tinned all over 
inside and out, it should be thoroughly cleaned, and the 
inside and outside should then be treated with saturated 
solution of sal-ammoniac and killed spirit of salts, and 
then dusted over with powdered sal-ammoniac. A vessel 
containing molten tin should now be in readiness, into 
which the article should be carefully plunged and washed. 
The article is then wiped with tow, plunged in cold clean 
water, dried with hot sawdust, and polished with whiting. 

Develoning Negative FUms.— Nothing will prevent 
films curling during development, unless some mechan- 
ical means of keeping flat the film is adopted. A very 
good plan, however, with small films such . as those of 
pocket kodaks is to roll the film, with the sensitised side 
outwards, roun d a bottle, the film being held in place with 
circular rubber bands;" the bottle is then revolved in a 
deep dish well filled with developing solution. Such treat- 
ment does not of course permit errors of exposure to be 
corrected during development. Special frames are made 
for printing from films, but ordinary frames can be used, 
the film being laid on glass. 



58 



Cyclopaedia of Mechanics. 



Painting Cardboard for Slate Pencil Writing.— 

The composition for painting eardboaxd so as to produce 
a sui'face that can be written on with slate pencil is 
similai- to that used for blackboards. Four ounces of 
shellac should be dissolved in 1 qt. of methylated spirit, 
and then ground with It oz. of flour emery, 2 oz. of ivory 
black, and 1 oz. of ultramarine blue. Other blackboard 
dressings are given on p. 230. Before using, the solution 
should be thoroughly shaken ; a little is then poured out 
into a dish and evenly applied with a brush. Two or 
more coats will b6 required. If the cardboard is very 
porous, a coat of very thin size may first be applied. 

Ordnance Datum. — The Ordnance datum is an 
imaginary horizontal plane extending over the whole 
country at the same height as the average mean level 
of the sea at Liverpool. This datum was fixed by the 
surveyors of the Ordnance Department, and the levels 
of districts are marked on the Ordnance mapa as being 
so many feet above the Ordnance datum, that is, above 
the average sea-level at Liverpool. The accompanying 
illustration shows a small portion of the si^ Ordnance 



oc 






87.7 



o 

B.M.S9')55 



'■^t:?' 




Ordnance Datum. 



map. At the corner of the house a bench-mark has been 
cut (these are usually about 1ft. 6 in. above the surface 
of the ground), and the figures Indicate that the point 
is at a height of 89'55ft. above Ordnance datum. The 
figure in the roadway indicates that the road at that 
point is about 87'7 ft. above the datum, the second place 
of decimals not being given. 

Polishing Brass Tube.— Brass tubes are prepared for 
polishing by being floated with a file, the teeth of which act 
as cutters and take off the top skin of the metal. Instead 
of floating, the tubes maybe polished bygrindingwithan 
emery wheel of about 180 fineness. This wheel, 12 in. in 
diameter, is fixed on the end of the polishing spindle 
by means of a false nose, the wheel being held in place 
by a nut screwed tight on the end of the thread of the 
upindle. On the bench is fixed a large compound slide- 
rest with an arrangement to carry the tube : a table is 
placed both in front and at back of the slide-rest to 
prevent the tube bobbing about. The advantage of the 
slide-rest is that any size of tube from fin. to 2 in. may 
be ground by simply raising or lowering the tool-holder 
and the tube carrier. The tube is placed on the carrier 
and adjusted till there is the slightest pressure or allow- 
ance for grinding by the wheel. The side of the wheel, 
not the edge, is used to grind with, and the tube is passed 
between the rest and the wheel, which takes off from the 
tube, with a circular motion, the thinnest possible 
amount of brass. Each side is served in this manner. 



Tubes are ground much more quickly by this method 
than by hand floating. After grinding, the tubes are- 
treated with ordinary polishing sand and flnaUy flnishe* 
off with the ordinary cotton mop and compo. The mopa- 
should be closely sewn together, the rows of stitching 
being about ^in. apart. They are further strengthened 
by bolting together with four ordinary snap-head, square- 
shank J-in. diameter iron pins with nuts. 

Cleaning ParafiBn Barrel.— Paraflin oil cannot be re- 
moved from the pores of a wooden barrel by chemical 
means. If the barrel is to be used for storing water, the 
oil could be removed by knocking out one end of the 
barrel and placing some lighted shavings in the barrel. 
After the oU has been burnt out the barrel may be- 
covered with boards and earth until the name has dis- 
appeared. The charcoal formed by the partial burning' 
of the wood in the interior of the barrel will be an 
advantage rather than otherwise in a water-butt. The- 
only alternative plan is to take one end out of the barrel 
and leave it in the open air until all the paraffin oil 
has evaporated, then give the inside of the barrel a 
coat of slaked lime, thinned to a cream with water. 
This will take longer, but will be safer than the flrst. 
method. 

Gramopbonc or Phonograpb Motor. — Ordinary 
brass clock wheels will do for a clockwork gramophone or 
phonograph motor. The motive power can be the main- 
spring and main- wheel complete of an eight-day American. 




Fig. 2 
Clockwork Motor for Gramophone or Phonograph. 

clock, but a stronger wheel would wear better. The train- 
consists of three wheels and pinions (see Figs. 1 and 2), 
and each wheel and pinion has a ratio of about 6 to 1. 
They are controlled by a weight governor like a steam- 
engine governor. The last wheel of the train carries- 
the discs and drives the governor. The wheels are 
mounted on studs on a bedplate, as in Fig. 1. The last 
one, carrying the discs, has a long "pipe." 

Recipe for Iron Cement.— Iron cement, used for 
filling up cracks and blowholes in iron castings by appli- 
cation with a hot iron, may be made as follows. Take 
by weight 2 parts of sulphur and 1 part of fine blaoklead. 
Place the sulphur in an old iroubowland hold over afire 
till the sulphur begins to melt ; then add the blacklead, 
and stir till all is well mixed and melted. Then pour on. 
an iron slab or smooth stone. To use the composition, a 
sufficient quantity is broken ujp, placed in the hole, and 
soldered in by means of a hot iron, in the same manner 
as a tinsmith solders sheets. As the fumes of sulphur 
are very annoying, the material must be melted in a 
good draught. 

Cork Paint for Ships.— " Cork " paint, sometimea- 
used on ships' ironwork to prevent it rusting, is com- 
posed principally of white lead, oil, varnish, and quick 
driers. After the surface to be treated has been sorapeO' 
and red leaded, the paint Is applied, and granulated cork 
is thrown on to the wet surface ; when thoroughly sax, 
the cork is painted over. This metl^od is only adopte* 
where the space is to be utilised for sleeping accommo- 
dation, and where the iron is not specified to be- 
covered with wood. This method is rarely employed in 
the merchant service, but In cruisers, where as little 
wood as possible is used, cork is freely made use of, heme 

fenerally mixed up in the paint shop of the yard where 
he work is done. 



Cyclopaedia of Mechanics. 



5!) 



Replacing Jewel Hole In Geneva Watch.— The 
jewel hole in the halance ot a Geneya watch is held 
In position hy the thin edge of its setting heiug 
burnished over the edge of the jewel. In fitting a 
new jewel hole, the old cine must be pushed out hy 
a flat-pointed peg, and the edge ot the setting raised 
by very carefully running the smooth point of a 
centre-punch round it. After fitting the new hole, 
which should go tightly into its recess, the thin edge 
must be once more burnished over the edge of the 
stone by running the centre-punch point round it, using 
a little oil as a lubricant. 

Fire-cracks in Plaster Walls.— Pii-e-oracks (which in 
some parts of England are called air-cracks) in plaster 
walls should be treated before giving the primary coat 
of paint with a coat of weak glue size (} lb. best Scotch 
glue to i gal. water) applied when the size is quite hot. 
Aliput 1 sq. yd. should be done at a time, and the size 
should be w^ped off at once with a piece ot old rag, the 
object being merely to fl.U aU the small cracks with 
size. The surface ot the plaster should be carefully 
wiped, for size should never be used on a plaster surface 
except for the purpose of filling cracks. 

Furnace for Wagon Springs.- Pig. 1 is a cross 
section and Fig. 2 a longitudinal section of a suitable 
furnace to be used when making railway wagon springs. 
A shows the firehole, B the blast inlets, and the cham- 
bers for the spring plates. The products of combustion 



the paint. 'When sufficient body has been laid on, the ( 
work will be ready for polishing ; this is done in most 
oases by rubbing down with a piece of felt dipped in 
tripoli or very finely powdered pumice-stone. Towards 
the end of the rubbing add a little oil, and when the 
work appears bright and glossy rub with oil only. Care 
must be taken that there is no grit in the polishing 
medium, or the work will be scratched aU over and 
spoUt. Finish off with a soft cotton or sUk duster. The 
brass part of the bedstead must be boiled for about 
twenty minutes in a strong solution of soda or potash- 
say i lb. ot potash and Igai. ot water : then well wash in 
clean cold water and dry. If the old lacquer has been 
removed, dip the parts in aquafortis by means of brass 
tongs ; when quite bright and clean, plunge in clean 
cold water, and dry in warm sawdust. The re-lacquering 
may then be done. It wiU be better to obtain the 
lacquer i-eady made. It must be applied with a large flat 
camel-hair brush, and the pieces of tubing laid on a hot 
stove or in an oven to set the lacquer. The various 
parts of the rails may now he put together, and the bed- 
stead set up again. 

Burnt Ballast for Mortar. — Where clean sharp 
sand cannot be had, burnt clay ballast or coke breeze 
are very good substitutes. Coal slack is not to be 
recommended. The coke breeze should be obtained 
from the nearest gasworks. The burnt ballast may 
be prepared in the following manner, the object being 
to burn the clay hard, as in brickm'aking. Four o^ 




^///■/.■/.■/// .:/.'/////,'/ // 



Fig. I 



Fig. 2 



s^^ 



Furnace for Wagon Springs. 



pass through flues in the bottom ot the third chamber, 
and thence under the floor to a stack in some con- 
venient position. The furnace should he built of brick 
and lined with firebrick, iron doors being fitted in the 
usual manner to open with chains, pulleys, and weights 
or levers. The stays are of cast iron. 

Preserving the Colour of Bath Stone.— Repeatedly 
cleaning oft the face of Bath or other stone by 
rubbing, glasspapering, etc., is to be deprecated, as it 
removes the natural skin, and, by opening the pores ot 
the stone, makes it absorbent. Treatment with Pluate 
or the Szerelmey liquid will give the surface of the 
stone a sUiceous skin, closing the pores, and making the 
stone non-absorbent. Neither ot these preservatives 
will appreciably alter the colour of the stone, although 
it is probable that in time the stone will become a little 
darker. An alternative plan is to paint the stone with a 
flatting coat of white lead mixed with turps and a very 
little linseed oil; this leaves a dead surface without 
gloss and not unlike that of distemper, and is also a pre- 
servative. 

Re-painting and Re-lacquerlng Bedstead,— In re- 
painting and re-lacquering a half-tester . bedstead it is 
necessai-y that first the brass headraU and footrail be 
taken to pieces. Thoroughly clean oft the whole of the 
old paint with a shavehook or other tool, then rub 
down the Iron perfectly smooth. Mix a quantity of 
one ot the following mirtures: (1) Ivory black; and 
shellac varnish. (2) Melt 41b. of asphaltum, and 
add lib. of hot balsam of copaiba, and when mixed 
thin down with hot oil of turpentine. (3) Grind ivory 
black very smooth with turps on a marble slab with a 
muller, and add copal varnish till the paint is ot the 
proper consistency j sulflcient varnish only must be used 
to cause the colours to bind and dry firm and work tree 
without becoming either sticky or shiny. The ironwork 
must then be carefully painted with the varnish by 
means of a camel-hair brush. About three to five coats 
must be given, each coat being dried in an oven heated 
to about 300° P., and if possible the heat must be grad- 
ually increased, but not to such a point as will calcine 



five old drain pipes, 9 in. or 12 in. diameter, are uiid 
in line with open joints. Around one end of the flue 
so formed is placed a heap ot wood, say 3 ft. high and 
6 ft. across the base. Over this conical shaped hea,p of 
wood is spread a good layer ot coal, and on the coal a 
layer of clay 6 in. or 8 in. thick may be deposited. Before 
attempting to burn the clay, it should be well turned, 
over, and tempered and dried in the air. When the fire 
is burning fairly well, more coal or breeze is added, and, 
when everything is red hot, another layer of clay. Mora' 
coal and more clay are in this manner added to the 
heap, until it becomes so large that further additions to 
it cannot conveniently be made. The fire is then allowed 
to die down, and the ballast is broken up and taken 
to the mortar mill. One cubic yard of clay measured in 
the solid, before digging, will, when burnt and broken 
up, make li cub. yd. to li cub. yd., and wiU weigh about 
Itou. From icwt. to Icwt. ot coal is required to burn 
1 cub. yd. ot clay ; or, according to some authorities, 
about 11 cub. yd. of breeze and 4 tons of coal, including 
slack, will burn 100 cub. yd. of clay. 

Taking Soundings of Ship's Well,— On each side of 
a ship's keelson there are "limber holes," which allow 
the bilge water to pass freely to the lowest part of 
the compartment, where there is an iron perforated 
casing to keep out rust chips or other sediment that 
would prevent, correct soundings. These casings are- 
about 1.5 in. in diameter, and one is fitted alongside 
the keelson in each compartment at the lowest point 
(which is aft in the fore-body compartments and 
forward In those ot the after-body). Any leakage or 
cargo sweat is tree to run down the skin between the 
frame or ribs to the Umbers. The sounding tool is an 
iron rod 2 ft. or 2 ft. 6 in. long, attached to a small line. 
The ship's carpenter chalks this rod and drops it into- 
the casing or well (keeping it vertical, of course). The- 
well soundings are entered in the I05 book in inches 
twice daUy. The iron rod is notched with a file at every 
inch. Some steamers with several compartments have 
limber holes in some of these which can be immediately 
closed, in case of collision, etc., by a screw sluice door 
manipulated from the main deck. 



•60 



Cyclopaedia of Mechanics. 



Bemovlng Cannon Flnlon front Keyless Watch.— 

In removing from akeylesB watch a cannon pinion that is 
flxedTery tightly, if there Is a square at the back take hold 
of it with a pair of cutting nippers in one hand and grasp 
the body of the cannon pinion with a pair of brass-nosed 

?liers held in the other hand, and twist the pinion off. 
f it cannot be removed in this manner, or if there is no 
squai-e at the back to hold, the centre arbor must be 
punched through with a small-pointed punch that wUl 
Just enter the cannon pinion without damaging it. The 
watch should r^st on a stake or piece of boxwood with a 
hole in it under the centre arbor. One smart tap should 
send the centre arbor through. 

Design lor a Carved Photo Frame.— Walnut, oak, 
or canary wood is suitable for constructing the photo- 
graph fi-ame here illustrated. It shoiUd be about Jin. 
or 1 in. thick, and 10| In. long by 9 in. wide. The outside 
margin is | in. i the size of the inner oval, from A to B, 
4fin.; f rom C to D 6i in. ; andtheouter oval is fin. larger 
all round. The oval could be made larger or smaller, to 
suit the photo ; the dotted lines show the method of con- 
struction. The design is sinlple and plain, and easy to 
mark on the wood. It the lines A B and C D are continued 
to the outer edges of the wood, they will divide it into four 



,^Yi^^villl'w■;■,v.^^l|.i\■^l^i^';M^a'■ '^,^'■'nl''.'.||■'■'''''■■|'.^! '': 

/.i i iii L liiiiiiM i i irffl4 n ii i i: Jiii III li)! d i, m™™^ 




with a piece of wire flattened at one end gently rub the 
solder along the seam until every part is joined. Bmall 
articles of iron may be Joined In a similarway with equal 
parts of copper and zinc, but if the iron is to be hammered 
much after soldering, 2 parts of copper and 1 part of zmo 
would be more suitable. "With these solders mix equal 
parts of the borax paste and grains of solder, and along 
the seams place sufficient of the mixture to soldei' them 
when melted. Some dry borax should also be Sept ready 
at hand, so that a little may be taken and th.own on 
the solder at any point where the material does not appear 
to be flowing freely. 

An Improved Saw-vice. — Figs. 1 and 2 show an 
ordinary pattern of joiners' saw-vice, differing from 
others only In the method of tightening up the jawsj 
Fig. 3 shows the bare-faced tenon for uprights, and 
Figs. 4, and 5 plan and elevation of eccentric clamp 
with rod and nuts. The rod is of i-in. round iron, 
with thread each end (mild steel would be more suit- 



Design for a Carved Photo Frame. 

-equal parts, and if one part of the design is sketched and 
taken off on tracing paper, it can be applied to each 
corner. The ground can be punched or cleaned. 

Brazing Brass and Iron.— A brazing spelter for small 
articles of brass consists of 5 parts copper, 3 parts zinc, 
and 2 parts silver, alloyed as explained on p. 63. If the 
seams are not required to standmuohworkingafter solder- 
ing, they may be joined edge to edge. "When seams are 
formed in this way, little nicks, about 4 in. apart, should 
be filed out along the edges, so that the solder flowing 
through the nicks during the soldering operation will 
render the joint sound. If the seam is to be worked after 
soldering, a small lap is necessary to ensure adequate 
strength. To form seams of this type, first thin the edge 
of the metal along the ends that are to form the seams, 
.about } in. in from the edge, so that when the two edges 
are lapped over each other the combined thickness at the 
seams will be the same as the single thickness of the 
metal at other parts. Cut a small cramp at the top and 
bottom of the seam, and fit the opposite edge in these 
cramps. After preparing the seams by either of the 
above methods, fasten binding wire round the articles 
BO as to hold the seams securely in position. Now 
powder some borax for use as a flux, and soak it in 
enough water to form a thick paste j place a little of 
this along the parts to be soldered, and gently heat 
the article by some suitable means, such as foot bel- 
lows and blowpipe, so that it will expand equally, 
and not disarrange the seam ; increase the temperature 
until the metal is a dull red, and then take a strip of the 
solder.dlp the end in the borax, and, holding the opposite 
-end with the pliers, rub the solder along the seam until a 
Jittle melts off. Keep the solder in a molten state, and 




Fig. 4 



An Improved Saw-vice. 

able), the bends being made by heating the iron red' 
hot lor the first, and nearly so when placed through 
the hole in the clamp and bent. This clamp must be 
shaped out, and the part where it will tighten on the 
stock by revolving should be smooth and true. Two 
•fi-in holes, which will be 6i in. down, are bored through 
both uprights to accommodate the ends of the rod, and 
collars may be let in flush at the back to tighten the 
nuts against. When the nuts are adjusted, a saw is 
instantly clamped by pressing the handle down as shown 
in Figs. 1 and 2. To release the saw, pull the handle of 
the eccentric claihp (lever) up. The position of the rod 
hole Is as shown on the handle side of the circle, and 
farthest from the stock. It will add to the grip to make 
uprights slightly curved outwards in the middle, and a 
2i-in. butt hinge will complete the vice. A sti'ip of 
vulcanised rubber or leather fastened along the inside 
edge (top) of jaws will improve the filing. 

Cutting Tin-plate.— If a number of pieces of tin-plate 
the same size and form are to be cut, it is usual to have a 
punch and die cut to the desired shape ; these are fitted 
to a press, and the pieces are then stamped out. If a 
limited number only is required, or if the pieces differ In 
size and shape, a circular hole smaller than the opening 
required i^ punched out with a hollow punch upon a lead 
piece J the nose of a pair of circular snips is then inserted 
through the hole and the metal out away to form an 
opening of the shape desired. 



Cyclopaedia of Mechanics. 



61 



Iiajrins Marble Mosaic Pavemont.— The materials 
commonly used for marble mosais paving are known as 
burnt marbles — that is, pure marbles burnt to the 
desired colours, such as rouge royal (red) and Russe 
cotto (red), with yellows, blues, greens, and greys of 
various shades, according to the amount ol time 8pen1> 
in burning. The natural marbles used in their original 
form are chiefly St. Ann's marble and Carrara and Irish 
green. The cubes may measure about f in. sctuare, though 
the size of the cubes depends on the area of the 
floor to be covared; but the cubes generally used are 
from i in. to f in. square, and are either sawn or cut by 
hand to the re(iuired dimensions. For each floor only 
one size of cube is used. The tesserae are fixed with a 
cementing material consisting of chalk lime slaked with 
water, and left in the open air for several days un^iil it is 
killed ; it is then sifted and mixed vrith a large pro- 
portion of fine crushed brick and water, and well 
beaten up with wooden beaters into a fine mellowed 
mortar ready for immediate use. The floor for the recep- 
tion of the mosaic is generally formed of Portland 
cement concrete, floated over to a taii-ly true face ; the 
mortar is now spread evenly on the floor, and the cubes 
of marble are laid to the required pattern, a small 
hammer being used for tapping the cubes in until they 
are solidly bedded. The floor is afterwards roUed with a 
moderately heavy roller, and then left for a time until 
the tesserae are set, when the ineiiualities on the surface 
of the floor are rubbed offl with specially constructed 
rubbers of sharp grit stone, water being freely used in 
the process. The face of the floor is rubbed very fine 



dip, after well pickling the articles, place in stronger 
nitric acid till a frothy appearance results ; then wash- 
in water and dip for a few seconds in the strongest- 
nitric acid. Wash in a bath containing a little dis- 
solved argol or cream of tartar, and dry in warm 
sawdust; then burnish the articles and lacquer in clear 
lacquer. A different but equally pleasing appearance- 
may be given to the brackets by bronzing. A bath that 
imparts to brass a shade from brown to a deep red can 
be made by dissolving 2 oz. of nitrate of iron and 2 oz. of 
hyposulphite of soda in Ipt. of water. Immerse the 
articles in this till they are of the required tint. For a 
shade from a pale green to a deep olive green, add 1 part 
of perchloride of iron to 2 parts of Water. For a dark 
green tint take 1 pt. of water, 1 oz. of nitric acid, and 
4oz. of nitrate of copper. A bronze which giVes a very 
good finish is composed of 1 part oxide of iron, 1 part 
white arsenic, and 12 parts hydrochloric acid. All' 

frease must first be removed from the articles and the 
ronze painted on with a brush. When dry the articles 
may be burnished in the usual way in part, or plain 
lacquered with a clear lacquer, or they may be plain 
varnished, according to taste. 

How to Mak^ a Chemical Tank for a Magio 
Lantern.— The following are instructions on making 
a small chemical tank for magic lantern experiments. 
Procure three glass plates 3i in. by H in. Prom one 
of these plates a half-circle must be cut out with a 
diamond, using a half-circle of wood as a guide. Canada 
balsam is used as the cement. It must be placed in a- 




FlG, I 




6cabbling Hammer for Laying Marble DIosaic. 



Fig. 2 



Chemical Tank for magic Lantern. 



and left quite smooth, and finally finished off with linen 
rubbers. Bui a method very generally followed is to 
arrange the cubes on paper in the workshop, the first 
step in carrying out the work being to get ont a design 
for the fioor. Prom this design copies are made at 
full-size scale, usually on brown paper, ready for the 
workmen. Great care must be taken to ascertain 
that the whole of the design is reversed on the brown 
paper, as, the cubes being laid on the paper in the work- 
shop, the paper would be uppermost on the job, and if 
the design were not reversed it would show the wrong 
way. The workman's paper, when finished, is cut up into 
convenient lengths (about 3 ft. 6 in.) , marked with num- 
bers from 1 consecutively, and handed over to the 
shop workmen, who require the following tools. A scab- 
bling hammer (see illustration) , about 11 in. lone and I in. 
square, tapered each end and fitted to a short handle, a 
pair of callipers, an iron block about 9 in. long by lin. 
by i in., granite rollers, straightedges, and rubbers. 
The workman now proceeds to pick out the necessary 
colours of cubes, dresses the cubes with the scabbling 
hammer to suit the design, and covers a portion of the 
design with a layer of gum, to which he attaches the 
cube.1, doing small portions at a time until the whole is 
completed. The design having been completed by the 
shop workmen, the whole is forwarded to the scene of 
the job. The mosaic layer is given a plan of the floor 
marked with numbers corresponding to those marked 
on the mosaia paper. Having laid the paving put on the 
job, the mosaic layer next prepares the cement, to which 
he fixes the marble slabs. After two or more days, the 
cement having become set, the paper is cleared oft, and 
ihe whole of the paving is subjected to conisiderable 
rubbing with fine grit stone, attached to a wood handle 
having a V-groove. The paving is completed by being 
rubbed to a level. 

Bronzing Brass Brackets.— Fancy bi-ass brackets, 
Bueh as gas brackets, are usually only dipped iu a 
nitric acid bath and burnished. If the dipping does not 
give the desired brightness, the brackets are dipped 
again and again, and thoroughly washed and dried be- 
tween each dipping. If the finish is not then suitable, 
the brackets may be dead dipped; this gives a dead 
yellow surface, and after the prominent parts are bur- 
nished presents a very artistic appearance. To dead 



saucer and baked in the oven until it is quite hard whei* 
cold. The three pieces of glass should now be heated in 
the oven or on an iron plate placed over a burner until 
they are too hot to be touched by the hand. The melted 
Canada balsam must now be spread with a smooth stick 
on both sides of the glass plate from which the half- 
circle has been cut, the other plates being pressed one 
on each side of it to remove all air bubbles. The 
whole should then be placed under a weight till cold. 
The tank thus made will appear like Pig. 1, and may 
be placed iu an ordinary carrier. With a lantern suit- 
able for experiments requiring a wider tank two 4i-in. 
by 4-i-in. plates may be used, cementing them together 
as described above by three pieces of plate glass, the- 
bottom piece 4i in. by J in. and the two side pieces each 
3i in. by I in. to form a rectangular tank 3i in. by 2J in. 
by about iin. deep (see Pig. 2). These measurements- 
may be altered if necessary to suit the lantern. 

Remedying Pinholes In Photographic Negatives. 

— Ordinary water colours are best lor stopping pinholes 
in negatives. Almost any colour will do ; but the work is 
more easily and better done when a colour that matches 
the tint of the negative is used, such as ivory black. 
The colour should be applied with a good sable brush, 
No. 2 being the best size. Bub a little of the paint on 
the smooth side of a piece of opal or even a piece of glass, 
and take up a little colour with the brush, drawing it 
with a circular motion to a fine point. If the b"ush is 
too wet the paint will run round the spot, and not in it. 
A white ring round a black spot only makes the spot 
more noticeable on a print. With the top of the brush 
touch the exact centre of the spot slowly but very deli- 
cately. In some few cases where the film has disappeared 
it is impossible to remove all traces of the spot ; and in 
such cases it is advisable to flU in the spot densely; on 
the negative, and paint over the white spot on the print. 
Exceedingly small pinholes, sometimes met with in 
clusters, are best left alone. A black spot on a print is 
less noticeable than a white one. Spots are usually the 
result of dusty slides or camera or dark room, the dust 
being finally deposited on the face of the plate. Soaking 
a plate in water before developing is liable with some 
plates to cause pinholes, the minute air balls that then 
form on the surface of the plate preventing the action 
of the deTeloper. 



62 



Cyclopaedia of Mechanics. 



Finishing Stair Balusters Green and Bronze,— 

Some stair Dalusters are to be painted two coats, finish- 
ing green and bronze. The first coat should be lead- 
colonr paint, and when this is dry give a coat of bronze 
green made from drop black (about one-third) and 
yellow ochre (about two-thirds). Thin with benzoline, 
adding a few drops of terebine as a drier. Put the 
broQze in a pint pot, cover it well with turpentine (which 
will extract the yerdigris), and let it stand for six or 
seven hours, after which the turpentine should be 
thrown awa.v and fresh turpentine added. Varnish the 
balusters, and when the varnish is nearly dry dip a piece 
of plush velvet in the bi-onze, and apply to the pro- 
jecting points of the balusters. This should be done 
while the varnish is tacky, so that the bronze may dry 
with the varnish. 

Making Copper Foot-warmer. — To mak? a foot- 
warmer, out a piece of No. 22 or No. 24 sheet copper 
to 22 in. long by 12 in. wide. Scour it thoroughly with 
wet sand, and tin one side of it over a coke fire with 
block tin, using sal-ammoniac as a fiux. When the 
tin has alloyed itself with the surface of the copper, 
wipe off with a pad of tow, and immediately immerse 
it in clean cold water, afterwards cleaning with silver 
sand, and then di-ying with hot sawdust. Punch a 
hole lor a feeder screw A (Pig. 1) in the centre of the 
length liUn. from the edge. The copper should now 
be planished with a planishing hammer on a tinsmith's 
bright anvil. This will close the " grain," tljus increasing 
the durability, as well as developing a bright, smooth 
surface. Two edges opposite each other should now be 
set off the ends on a hatchet stake, so that when the 
eopper is bent to shape the edges will clip each other. 
The bending can best be done over a narrow mandrel. 



all over, so that the leather ,iust changes its colour ; then 
scrape some buff ball all over the sole while it Is damp. 
Hold the boot firmly between the knees, and with a 
hare's toot or piece of soft fiaunel dab the buff ball down 
to cover the sole. Finish by brushing off any loose dust 
with the hare's foot. 

Wiping Joints on Copper Pipes.— Wiped joints on 
copper pipes are longer than wiped joints on lead or 
composition pipes. Copper pipes 2 in. or more m diameter 
have joints from 2Un. to Sin. long; 4-in. pipes have 
joints about 4 in. long; but it must he remembered 
that whilst reasonable length and thickness of joint 
are necessary to enable the copper pipe to withstand 
pressure and strain, the maximum time of service 
does not depend on the length or thickness of the 
joint as in lead-pipe work. That which determines 
practically the life of the joint is the extent of pipe 
which is carefully tinned before forming the wiped joint. 
If the interiors of the two pipe ends are tinned, say, for 
6 in . or 8 in. , on cutting open the joint in a tew years time, 
it is found that the tinning has diminished to 2in. or 
3in., a corroding action having taken place at the end of 
the tinning ; for this reason it is advisable that the tin- 
ning be fairly thick, so as to retard the separation and 
ultimate tailure of the joint. In tinning copper, first 
thoroughly clean it with dilute sulphuric acid or scour 
with sand and water, and then rinse It with chloride or 
zinc known as killed spirit. Melt some pure tin, 
throw in sal-ammoniac as a flux, and dip the copper in 
the tin, or pour or rub the latter over the copper. In 
pipes forming a portion of a distillery plant it is espe- 
cially important that no nntinned spots are left on 
the interiors of the pipe ends, as at such spots the 
destruction of the tinning commences at once. In Fig. 1, 
which is a part sectional view of the two pipe ends pro- 






.im .i.t'ii'. 




, -^' 


"^A^^" 


-t=:jn- 



















Fid f 
Making Copper Foot-warmer. 



Fig. 2 



and the edges must be " grooved " inside. When this 
has been done the section will appear as in Fig. 2. 
Solder the feeder screw in the hole Irom the inside, and 
similarly the grooved joint, leaving a good body of metal 
on each. This constitutes the body of the toot-warmer. 
To make the ends, up-end the body on a piece of copper, 
and marli around. Allow a i-in. edge extra, cut the 
copper, and mark and cut out another one from it. 
These pieces should be cleaned, tinned, and planished, 
etc., as previously described. Then they should be 
slightly hollowed (both together) on a wooden block 
with a hollowing hammer. Now crease or " jenny " the 
edges so as to fit the body tightly. Before these pieces 
are finally fixed, two handles B (Fig. 1) must be made 
from No. 8 brass wire, each with a copper plate which 
is riveted to the end, as shown. Solder over the heads 
of the rivets inside, fit each end on, and solder well 
round. The superfluous solder may be removed by a 
steel scraper or a smooth file. Rub well with emery 
cloth, andr finish with crocus and oU. 

Particulars of Cellulose — Cellulose is an organic 
product having the same composition as starch, and" 
is a similar composition to sugar, i.e. CbHioOb. The 
purest cellulose is sold by chemists, etc., as cotton-wool 
for medical purposes; the cotton fibres, linen, wood of 
all kinds, paper, etc., are aU more or less impure forms 
of cellulose. 

Buff Balling Bottoms of Boots.— To make out the 
Bottom of a boot, the sole should be buffed or scraped 
with the buff knife, that has been well sharpened till 
it has a keen, regular edge. Only the first layer of 
grain is taken off the sole ; when this has been care- 
fully done and the sole has been well sandpapered, it 
should have a fine velvet-like surface. It is, however, 
very hard to produce in this way a white bottom upon 
bad leather, or upon good leather improperly worked. 
With a soft brush remove all the dust of leather made 
by this process, and scrape some buff ball all over the 
bottom, and with a fine piece of sandpaper work it 
evenly all over the sole, and then smooth it down with 
the hack of the paper. With a. clean soft piece of fiannel, 
lightly damp down the whole of the sole, doing it evenly 




'fro. 2 --- 
Wiping Joints on Copper Pipes. 



pared for jointing, A shows the extent of the tinning, 
which is on the exterior and interior of the pipe ends 
and on the edges also. Fig. 2 shows the tinned ends 
slipped together ready for wiping, the form of the re- 
quired joint being shown by the dotted lines. The pipe 
is strengthened by putting one pipe within the other, 
and the corrosion of the tinning is arrested when it 
reaches the lap. If sufficient lap is eiven, the pipe may 
be handled before the joint is wiped— a great convenience. 
The pipe ends are placed together, when practicable, 
over the iron pot containing the molten solder, which is 
then poured continuously over the joint until a heat is 
got up. This practice is not possible with lead ' or brass 
pipes, because in the one case the lead would melt, and 
in the other the molten zinc would leave the brass and 
ruin the solder. When the pipes cannot be moved, a 
grain scoop (a kind of shovel) is placed beneath the joint 
and the solder poured on rapidly. When a thorough 
heat has been obtained, the joint can be wiped, with the 
aid of a cloth and of the mushy solder from the scoop, 
in much the same way as a joint on a lead pipe is wiped, 
the latter operation being described on p. 88. 

Adjusting a Watch In Positions.— Provided there 
are no faults in the escapement, pivots, or jewel holes, 
the adjusting of a watch in positions is mainly a 
question of exact poise of the balance. The balance, 
with its pivots perfectly clean, should be placed on a 
poising tool and carefully tested. In a plain balance, 
filing the inside under edge of the rim will poise it. In a 
compensation balance, small errors can be altered by 
manipulating the four " c[uarter screws "—that is, those 
with long taps. Larger errors must be corrected by 
altering the weight of the screws. When perfectly poised, 
the watch will be very nearly correct in different posi- 
tions. A loss in any one position generally indicates 
that when the movement is held in that position, and the 
balance is at rest, the top of the balance rim Is too 
heavy. 

Removing Ink Stains from Bone Handles. — To 

remove dirt from bone knife-handles scrub with hot 
soap and water, and wash weU with clean water ; rub on 
a solution of oxalic acid to remove ink Stains. Again 
wash, dry, and polish with a chamois leather and whiting. 



Cyclopaedia of Mechanics. 



63 



Traveller's Sample Case.— Figs. 1 to 5 show the con- 
■etruotlon of a traveller's sai^ple case. Good red deal, 
i)iroh, beech, or other similar hardwood, i in. to 1 in. 
thick, may he used, according to strength and other 
Tequirements. The angles should he dovetailed to- 
sgether, and the boards jointed and eross-tongued, 
as shown at Fig. 4. To prevent dust, etc., getting in, a 
fillet about Uin. by i in. should be naUed round so as to 
project into the lid when closed (see Fig. 3). If the 
staples are made as shown at Pig. 5, they can be screwed 
to the front of the rim of the lid, and the returned piece 
shown at A (Fig. 5) can be let in and screwed to the 
underside of the lid ; this will prevent it being broken 
oH. The eye and plate can be made so that the eye 



woodwork for flush seams to be wiped upright in the 
centre of their length. For rain water, the sides and. 
ends should be of 7-lb. lead, and the bottom of 8-lb. lead ; 
but it economy must be studied, 6-lb. lead sides and 
ends, and 7-lb. lead bottom, would do. To linethe tank, 
first put in the sides, then the ends, and the bottom 
last of all. After the lead is in position, the upright 
flush seams and the upright angles should be soldered, 
then the bottom flush seams, and lastly the bottom 
angles. It is assumed that suflJcient knowledge is 
possessed to arrange the laps so that the solder 
will not run through when wiping, and also to 
prepare the work for soldering. Upright stiffening 
pieces wiped on to the sides are better than dots; but 




■J — 1 


hU — 


-HLJh 




h 


nn 




E> 


n — 


-^■■.l^ 


— r.\- 


H:: 



Fig I 




Fig. 2 

Traveller's Sample Case. 



passes through the front, the plate being screwed to tlfe 
inside; it is thus not likely to he broken off or un- 
screwed from the outside. Two padlocks may be used, 
or a rod and one lock, as shown in the illustrations. For 
ordinary purposes, one staple, eye, and lock would be 
found sufficient. 

Lining a Wooden Tank witti Lead,— In lining with 
lead a wooden tank 20 ft. by 9 ft. by 4 ft. deep, first 
divide the bottom of the tank into three parts. This 
gives two seams across the bottom, and where the seams 
come the woodwork should he dished tor the soldering 
to be wiped flush. The lead for each end of the tank 
can he in one piece, and if plenty of help is available, 
the sides could also be each in one piece. But if the 
tank is in a cramped position where the extra hands 
cannot ezert their full strength, each of the sides can 
be lined with two pieces, dishings being made in the 



if it is found necessary to fix stay rods to keep the 
sides from bulging outwards, these rods would also help 
to support the lead, and prevent it from bagging as the 
tank is emptied of water. 

Silver Solder for Soldering Copper.— A silver solder 
for soldering copper is composed of 5 parts of copper, 
3 parts of zinc, and 2 parts of silver. Melt the copper 
first, then add the silver, and lastly the zinc ; directly 
the zinc is immersed, rapidly stir the alloy so as to 
render its composition equal throughout, and then 
oast it in a small ingot mould. The ingot is 
then rolled down to form a small sheet equal to 
about No. 18 B.W.G. gauge in thickness, and from 
this narrow strips are cut as required. Ordinary 
solder may be converted into fine solder by melting 
and then adding the silver in the proportion given 
above. 



64 



Cyclopaedia of Mechanics. 



Separating Gold from Ashes.— A simple -way ot 
separating gold from ashes is to mix the aahea with 
borax ana melt down in a crucible. For this purpose 
the highest heat of a wind furnace will be required. 
It the ashes contain traces of other metals besides gold, 
It would be best to boil first with water several times 
to get rid of soluble matter, then with aqua regla 
(3 parts of strong hydrochloric acid to 1 part of 
strong nitric acid) in a porcelain dish, using a fume 
chamber or chimney to carry away the fumes. After 
boiling for several hours, water may be added and the 
liquid filtered. The filtrate will contain the gold and 
other metals as chloride. A solution of ferrous sulphate 
(green vitriol) should be added in excess, and the liquid 
boiled. A brown precipitate will come down ; this is 
pure metallic gold. It may be filtered off, washed several 
times with water, and dried, when it will form a reddish- 
brown powder. It may be melted down in a crucible or in 
a furnace, or fused to a button of metal on charcoal 
before the blowpipe. 

Waterproofing Fishing 
Lines. — Plaited silk fishing 
lines are waterproofed by soak- 
ing in equal parts of boiled 
linseed oil ana copal varnish, 
then stretching in some con- 
venient position to dry, at the 
same time wiping off super- 
fluous dressing with a rag. Dry- 
ing will take a considerable 
time; to accelerate it, I part of 
gold. size may be used instead 
of the varnish to 2 parts ot 
boiled oil. 

Frame for Wire Blind. — 

Fig. 1 shows the general form 
of the frame for a wire window 




may be used so long as provision is made In the dark 
slide to catch the drippings from the plates ; a fold of 
blotting paper will answer this purpose. The following 
materials wUl be required for preparing and developing- 
the plates. Mawson's iodised collodion i oz., silver 
nitrate 1 oz., a tew pounds of hypo, alcohol 1 oz., acetic- 
acid 1 oz., sulphate ot iron 1 oz., an ebonite dippei\ and 
some pieces ot clean glass free from air bells. Make 
up the following solutions. SUver 6o(/i.— Silver nitrate 
roz., distilled water II oz.. Iodine I gr., nitric acid 2 drops. 
BeveJoper.— Sulphate of iron loz., alcohol Joz., acetic 
acid ioz., water 4iOZ. Clean the glass by first swHUng- 
with water, and, if greasy, washing with a powerful 
alkali such as caustic soda, and again swilling. Allow 
the glass to dry spontaneously. When dry, wipe free of 
dust, and pour in the centre of the plate a pool ot the- 
iodised collodion, as in varnishing a negative, and flow 
first to the top right-hand comer, next to top left-hand 
corner, then to the bottom left-hand corner, where the 
plate is balanced by the tip of the thumb, and from the- 
bottom right-hand corner pour 
off the excess into the bottle. 
As soon as the collodion has set 
(which is when the surface be- 
comes dull) Immerse the plate 
in the silver bath by means of 
the dipper, lowering gently into- 
■the solution, where it should 
remain, rocking occasionally, 
for about two minutes. As soon 
as the silver solution wets the 
plate evenly (this takes longer 
in cold weather) the plate is 
sensitised. The sensitising is 
done in the dark room, and a. 
flat porcelain dish may be used 
to contain the bath. The plate 
is gently removed from th» 
bath, and when it has finished 



FlQ. I 






FiQ 3 



Frame for Wire Blind. 
« 



FiQ. 2 



blind. Fig. 2 is an elevation of the joint (A, Pig. 1)1 to a 
larger scale. The tenon, mortise, haunch, and wedges 
are indicated by dotted lines. Pig. 3 shows the con- 
struction of the joint, mitreing ot the head which is 
stuck on the solid, and the rebate formed for the 
movable bead, which is not shown. The beads should 
be about Jin. 

Filtering Cycle Oil.— Dirty cycle or other machineiT 
oil may be filtered through cotton-wool, flannel; or any 
similar material without affecting its lubricating pro- 
perties. Plannel is not so good as closely packed cotton- 
wool, because the flbres are openly felted! and the finer 
dirt can get through. Closely packed cotton-wool makes 
a slow filter. The best fllterlng arrangement is a glass 
or tin funnel placed in a bottle, and a circle of best 
white blotting paper folded twice and opened to fit the 
funnel. The oil will pass pretty quickly through the 
paper. When the blotting paper begins to plug up it 
may be removed and fresh paper substituted. 

Wet-plate Photography.— In wet-plate photography 
the plates are prepared as they are required, and are 
developed immediately after exposure. Any camera 



dripping it is placed on the wires in the dark slide and 
exposed in the ordinary way, though for a longer time 
than a dry plate. The plate must be kept in a vertical 
position. On removal from the slide the plate is held 
in the hand, as in coating, and is flooded with the- 
developer. Coating the plate, sensitising, exposing, 
and developing should follow each ot)ier as quickly as 
possible, or various defects will occur in the plate. 
As soon as development is complete the plate is im- 
mersed in hypo 1 oz., water 6 oz. The used developer and 
the drippings should be filtered through cotton-wool 
and saved for use in cases ot over-exposure. Should th& 
image be too weak, it may be strengthened or Intenslfiea 
by flooding with pyro 4 gr., water 2oz.,8ilver bath Idr., 
and 10 per cent, solution of -880 ammonia a few drops. Wet 
plates may be varnished with ordinary negative varnish. 
The ferrotype is merely the wet collodion process for 
producing positive Images on a metal, instead of glass, 
plate, the image being reversed as regards right and 
left. The only advantages of the wet collodion process 
are cheapness, extreme density and contrast in image, 
and flneness of grain. The process, being dirty and ex- 
tremely slow, Is now seldom used except by itineranti 
photographers. 



Cyclopaedia of Mechanics. 



65 



t'ementing Broken Marble.— As a cement for white 
mai'ble, use fine plaster-oF-Parls mixed to tiie oonsistenoy 
of thiols cream. A thoroughly satisfactory job, how- 
ever, cannot be made in the case of a mantelpiece, as 
the repair will show in time. For black or coloured 
marble use brown or orange lac, obtainable from dry- 
salters or chemists. Warm the broken pieces of mai-ble 
before the fire, then place on the lac, and when melted 
press the two pieces together until firmly set-a few 
minutes will sufBce ; the superfluous lac should be 
sctueezed out whilst it is warm. If desired, the lac may 
be prepared in sticks by melting It on a hot plate, adding 
the requisite colouring matter in the shape of oxides, 
and then rolling into sticks similar to sealing wax. 

Tool Chest lor a Light Coach Body Maker.— A tool 
chest suitable for a light coach body maker may be 
made of 1-m. sound red deal, free from knots and 
shakes and perfectly dry. The front and back, should 
be jointed and glued in the centre as A (Fig. 1), the 
ends having two joints as B (Fig. 2), so that the 
strain is not on a direct line at the .joints. The sides 
and ends should be dovetailed together, and should 
be 2 ft. 8i in. long outside by 1 ft. 6 in. deep over all 
by 1ft. 6in. wide, the plinths being fixed outside this 
measure. The bottom is screwed on crossways of the 
length, and is tongued together as shown in Fig. 3. 
The top is made up lengthways of the grain, glued 



then finer, then the finest. Now rub briskly with a piece 
of rag that has been dipped in oil and then into the 
dust, etc., which has come from the horns during the 
scraping, filing, etc. The horns should then be smartly 
rubbed with a rag dipped in whiting and sulphuric acid 
or vinegar, then with a rag dipped in oil and putty 
powder (oxide of tin). Now well rub the horns With a 
dry cloth, then with crumpled paper, and finally with 
the bare palm. The rubbmg at each stage must be 
thorough ; and between every two steps a good dusting 
of the horn should be given to prevent the larger parti- 
cles of the one stage scratching the smoother surface 
gained in the succeeding stage. 

Heat Insulating Composition.— The following recipe 
for a non-conducting composition has been given for use 
with steam pipes, etc. In water, mix fireclay with four 
times the ctuantity of small coal ashes to the consist- 
ency of thin mortar. Then mix equal quantities of dry 
calcined plaster and fiour, each constituent equalling in 
quantity the amount of fireclay previously used. Add 
to the ash mixture. Two coats should be used, with a 
setting coat outside, as when plastering a wall. 

Cutting Slot In Top of Turned Pillar.— When it is 

required to cut a slot in the top of a turned pillar, 
a box similar to the accompanying diagram should 
be constructed, and in each piece of board two kerfs 




Tool Chest for a Light Coach Body Maker. 



Cutting Slot In Top of Turned PlUar. 



and jointed in the same manner as the front, and 
fixed on by screws. The whole is cleaned off, and 
the plinths (Figs. 1 to 4), which are 3i in. deep by 
i in. thick, put on flush with the top and bottom, and 
mitred together at the corners. To form the lid, gauge 
round from the top edge 2 in. down (see D, Figs. 1 to 
3) i saw round, keeping true to the line, and then 
plane off the edges true to a fit. The lid will now be 
just deep enough to cari-y a hand and tenon saw 
when the tools have to be packed for transit. The lid 
may be hung with 3J-in. wrought butts or cranked 
cross-garnet hinges, and should have a good double 
action spring look. For lifting the box, two pieces 
of beech 3 in. wide, shaped as E (Figs. 1 and 3), are 
fixed on the ends by screws from the inside. Holes 
are made just above the centre (see Figs. 1 and 3) ; 
these carry rope handles. The Interior of the chest 
is shown at Figs. 3 and i, fillets being fixed on the 
ends to carry a light framing to form the tray 1? (Figs. 
3 and i) and recess for the drawers G. This framing 
is supported by a strut fixed inside the casing H, 
which is made to slide forward ; the space beneath the 
drawers is for working drawings, sizes, etc. A small 
board J (Figs. 3 and 4) 3i in. deep Is fixed on the bottom 
and ends to carry compass, smooth, concave, and tee 
planes. Coat the inside of the chest with pale gold size, 
and the outside with good lead colour. 

Polishing Goat's Horns.— In polishing a pair of goat's 
horns, remove any rough or uneven parts with a spoke- 
shave, then well scrape all oyer with a cabinet-maker's 
steel scraper or with the edges at the sides of a wood- 
worker's chisel. When the horn is fairly smooth, go 
over it with a rasp or file, followed by coarse sandpaper, 

S 



should be truly made. The pillar can then be fixed true 
in the box by a few wooden wedges, as indicated at A and 
B. The head should next be sawn ay allowing the saw to 
work in the kerfs as when using a mitre box. 

Modelling In Papier-mach^. — In making anima) 
heads with papier-mache, either a natural skull or one 
modelled in clay is obtained, and from this a plaster 
mould is taken. In this mould papier-mlchfi is forced, or 
sheet after sheet of pasted paper is pressed In every 
direction, and forced well into the hollows. When dry, 
the material easily comes away from the mould. To 
make papier-mioh6, tear into small pieces a number of 
old newspapers, and boil until quite soft. The pulp 
should then be removed from the fire and squeezed, 
some thin glue and plaster-of-Paris added, and the 
whole beaten well together. If the material is too di'y, 
add glue ; it too sticky, add plaster. When rubbed on 
the hands It should leave a very thin coating. 

Cleaning Aquarium Shells.— It, is impossible to keep 
delicate shells fresh and clean at the bottom of an 
aquarium, for they quickly become covered with a green 
aquatic growth that defies all efforts to be sci'ubbed off. 
The shells may be cleaned by plunging them in a boiling 
mixture of 1 part of hydrochloric acid to 10 parts of water 
Hold them with wooden tongs, and remove after one 
second to clean cold water. Repeat the operation if 
necessary, but if the shells remain in the acid beyond 
the prescribed time they will be eaten in holes, if not 
altogether dissolved. If the shells are to be replaced in 
the aquarium, it is not worth while to clean them re- 
peatedly. Introduce a few fresh-water snails into the 
aquarium, and they will keep down the green growth. 



66 



Cyclopaedia of Mechanics. 



Particulars of Oil of Turpentine.— Oil of turpen- 
tine, spirit of turpentine, and ordinary or common 
turpentine are all the same thing. Crude tui'pen- 
tine is turpentine as it is derived direct from the 
pine trees. Oil of turpentine really means the' essen- 
tial or volatile oil of turpentine after distillation. Oil 
of turpentine must not be classed with the ordinary 
kinds of oils, such as olive oil, etc., which are non- 
volatile, and have a different composition altogether. 
There is an oil of turpentine known as fat oil of turpen- 
tine, but this is simply ordinary turpentine that has 
been exposed to air for some time and has become 
thickened or partly resinifled by oxidation. 

Yellow Stain for Venetian Blinds,— A high-class 
satin stain lor use on Venetian blind laths previous 
to varnishing can be obtained by dissolving 1 oz. of 
gamboge in 1 pt. of methylated spirit. A cheaper plan 
would be to mix dry yellow ochre, or 2 parts lemon and 1 
part orange chrome, in weak glue size. This latier 
mixture should be brushed on, the surplus being wiped 
oft with soft rag. 

Determining Bevels for Joints of Oval Cask.— In 

finding the ooi-rect bevels for the joints of an oval cask 
first set out the oval or ellipse, and a good method of 
doine this is shown by the illustration. Let A B 
and C D be the given diameters. Divide O into three 
equal parts. On line AB mark off A3 and B4, each 
equal to O 2. Make 5 equal to O 2 ; then draw the radial 
lines from 2 and 6, passing through 3 and i as shown. 



ing a continuous cool supply. The collar platei are 
stamped out of Uo. 6 fender plate, and when solid flaps 
are made in the axle, these plates have to be out across one 
side to allow of bending back to get them on between 
the collar and the flap. 

A Watch-case Galvanometer. -To make a simple 
galvanometer as in Pig. 1, get an old brass watch 
case with one of the brass plates removed. In the 
centre of this drill a very small hole to suit an end- 
stone, such as jewellers use in watches. Then cut a 
piece of brass to fit across the diameter of the plate, 
i in. wide and A in. thick. Drill a hole at each end, and 
get two small brass pillars for the ends, about i in. 
long by iin. in diameter, to raise the cross-bar from the 
plate. Then driU a central hole in the bar, and put an 
endstone in this. Taper a piece of watch spring each 
end from the centre to form a pointer, drill a iVin. 
hols in the middle of it, fit a shaft In tight to the 
hand, and magnetise the pointer ; pivot the shaft at the 





Fig. I 



Determining Bevels for Joints of Oval Cask. 

Then 2 and 5 will be the centres for the larger curves, 
and 3 and i for the smaller. Hert set out the staves as 
shown. It will be seen that two bevels will be required. 
For the sharper-curved staves, as at B, join the points 6 
and 7, then join the radial line 7 4, and draw E bevel as 
shown; the bevel at P can be obtained in a similar 
manner. The bevels here given are for application at 
the centre of the staves. 

Forging Axles for Vehicles.- The iron for vehicle 
axles should be of the best quality. The method of work- 
ing is as follows. A number of small bars are put up in 
a bundle sufficient to make an arm, and bound with iron 
rod to prevent falling about when working. The arm is 
then placed in the furnace, and thoroughly welded to- 
gether. Whilst this is being done it is worked somewhat 
to the required shape. The collars are, now made and 
welded on. For this purpose dies, or top and bottom 
tools, are used, the arm being worked at as great a heat 
as possible without burning, lighter heats being taken 
for finishing to the size required with light blows ; after- 
wards turn and fit the axles. To case-farden, place the 
articles in an iron box or casing large enough to contain 
a packing of 2 in. or 3 in. of the hardening compound 
around each arm. The box should be sealedu^ air-tight 
at both ends. The compound generally used is leather 
shreds, ground raw bones, hydrooarbonated bone black, 
and sal soda, the whole being placed in a furnace and 
kept at a good heat for ten or twelve hours j then remove 
the articles from the box and cool out thoroughly. 
Where an extra hard casing is required the articles are 
re-heated, the box being filled with powdered potash and 
kept in the furnace until the potash is consumed. 
Where large quantities of axles have to be cooled out 
the cooling tub should be arranged to have an inlet of 
cold water at the bottom, so that the water made warm 
by the work would flow out over the top, thereby ensur- 




Watch-case Galvanometer. 



endstones. Next cut a piece of tin to the shape of 
Fig. 2, lap it with silk tape, varnish, and lap agalt 
with about 8 ft. or 9 ft. of No. 28 S.W.G. silk-covered wire. 
Next get a piece of spring steel, A in. in diameter by 
li in. long, magnetise it, and fasten in cross section to 
the horseshoe magnet after taping and varnishing. 
Fasten these two magnets to the back of the brass plate 
by means of a short piece of ebonite and small screws 
at the ends. Drill two holes at each side of the case for 
the reception of two terminals, and connect as shown 
in Fig. 1. A scale, also, graduated as shown, should be 
afoxed. 

Soldering a Joint In a Watch Case.— To solder a joint 
in a watch case, the old joint must first be filed off clean. 
This should leave a semicircular groove in which the new 
joint can lie true. The joint is cut from drawn sUver or 
gold tube. Place it in its groove, having first wetted It 
with borax paste and water. Along Its side place a long 
thin strip of silver or gold solder, and apply a blowpipe 
flame to the case near the joint until it is well hot j then 
direct the fiame on the joint until the solder runs. As 
soon as the solder sets, and while the case is hot, plunge 
it into a pickle made of sulphuric acid 1 part and water 
9 parts, then wash in plenty of' water, and clean up. 
Before soldering, unpin the back, bezel, and dome, and 
take out the bow, push piece, and any steel springs so 
that they may escape injury from the heat. 



Cyclopaedia of Mechanics. 



67 



Making Black Crayons.— To make black crayons, 
mix 10 parts of pipeclay, 1 to H parts of lampblack, 
and i part of Prussian blue with water to a stiff paste. 
Well knead all the ingredients together. Allow the paste 
to remain for several days, then roll out on a board and 
cut into lengths. A better method, however, would be 
to press the crayons in a mould ; they would be-harder, 
more homogeneous, and less liable to break. 

Green Stain for Oak Picture Mouldings.— To stain 
oak picture mouldings a bronze green, mix bronze green, 
procurable at paint stores, in hot vinegar or in dilute 
French polish. If the mouldings are to be polished, 
mbdng In vinegar is advised. Some of the dry colour 
may then be mixed with the grain filler and also with 
the varnish, which will be required on oak in order to 
gain a solid body. 

Acetylene Gas Generator for Magic Lantern.— 

Herewith is a sketch (one-eighth full size) of a portable 
and au.tomatl6 acetylene gas generator for use with a 
magic lantern. The apparatus works well, and will 



work IS detached from the brickwork. The discoloured 
marble may, however, be bleached by treating It with a 
solution of soap lyes and whiting, but this bleaching 
;will. not be permanent. Mix the soap lyes and whiting 
to the consistency of a paste, and apply a good coating 
with an old brush. Let this paste remain On the marble 
lor a couple of days, then wash off with clean water- rain- 
water for preference— repeating the process two or three 
times until the stains have been removed. To make the 
lyes, obtain, say, 71b. of American potash from the dry- 
salters, and dissolve in a pailful of rainwater. The lye 
IS of such a caustic nature that it is dangerous to fingers 
and nads. H, therefore, any of the liquid gets on the 
hands, they should be at once well washed In water 
ppntaining a few drops of vinegar or acid to neutralise 
the alkali. 

Making Railway Coupling Shackles.— To get railway 
couplings to stand, the grain of the iron in the shackles 
must follow round the eyes. To accomplish this, the bar 
IS first nicked with the fuUer as shown at A (Pig. 1), and 
the end drawn out to form a scarf as at B, which is bent 




Acetylene Gas Generator for Magic 
Lantern. 



give about 400 candle-power for about two and a 
half hours. In the illustration the carbide is shown 
on top of the lime residue. A is the pipe leading to 
the lantern, the lamp for which has four burners. 

Follsliing Tin-plate Goods.— Tin-plate goods, before 
being polished, are scoured by being held against a 
revolving mop greased sufficiently for the purpose by 
contact with a tallow candle. Finish by polishing with 
a dry mop on which some Sheffield lime is placed. 
When polishing tinware, the mop should be run at a 
speed iust sufficient to cause it to stand out stiff i it the 
lathe is run at too high a spaed, the mop will remove 
some of the soft surface tin. 

Stains on Marble.— Marble erections against a back- 
ing of brickwork will in a year or so's time show a 
brownish stain, and probably this will gradually spread. 
The stains are caused by the close proximity of the 
marble to the brickwork. The marble, being of a 
crystalline and somewhat absorptive nature, has 
attracted the damp from the brickwork, and so become 
discoloured. In nearly all walls, especially those re- 
cently built, constant evaporation is taking place, and 
the effect of this evaporation is to draw the damp 
from the middle of the wall towards the surface. Marble 
work, therefore, should never be fixed solidly to a wall, 
but an air space should be left between it and the brick- 
work, with an open joint here and there to aUow for the 
condensation that invariably takes place. It may be 
objected that, by allowing an air space, solid fixing could 
not be obtained, but this objection may be overcome by 
the jadlcious use of brass or copper cramps. There 
is no permanent remedy tor the stains unless the marble- 




Fia2 



Making Railway Coupling Shackles. 

over as at and welded, the eyes D being finished on the 
anvU with a pair of tools and a punch. The part 
between the two eyei is then heated and the bar placed 
with one of the eyes on the stud of a bending block A 
(Fig. 2), and fixed by means of a cotter at B. One of the 
horns of a bending tool and D (Fig. 2) is placed in a hole 
E in the block, and the handle pulled round towards the 
arrow F, the bar following in the direction shown by the 
arrow G until the shackle is bent to the required shape. 
Pig. 2 shows the bending block in plan, and and D 
are two views of the bending tool. The shackles are 
made of 1-in. to IJ-in. Lowmoor or Yorkshire iron, 
according to the class of vehicles on which they are 
used. 

Cleaning Leather-work Brackets.— To clean a pair 
of leather-work brackets mix a little carbonate of mag- 
nesia with benzoline to form a thin fluid, and apply it, 
in large quantity, quickly to the leather. Place the 
brackets in the open air to dry, then with a light feather 
brush dust out all the dry magnesia. If this does not 
serve the purpose, the only way of giving the bracket a 
good appearance will be to cover the leather with a buff 
flatting paint of a suitable coloui'. 



68 



Cyclopsedia of Mechanics. 



How to nse a Twaddel's Hydrometer.— Twaddel's 
hydrometers are sold in sets of six or separately ; tliey 
read as follows -.— 

No. 1. 0° to 24° = sp. gr. of I'OO to 112. 



2. 24° 


, -ix" = 


1-12 , 


1-24 


3. 48° 


, 74° = 


1-21 , 


, 1-37 


4. 74° 


, 102° = 


1-37 , 


, l-.ll 


5. 102° 


, 138° = 


1-51 , 


, vm 


6. 138° 


, no« = 


1-69 , 


, 51-8 



The specific gravity of a licLuld is determined by floating 
one of the hydrometers in some of the liquid, contained 
In a tall glass cylinder ; if the hydrometer is suitable for 
tliis particular liquid, the instrument will sink until the 
surface of the liquid coincides with some mark on the 
stem of the hydrometer. Suppose the sti'ength of a 
caustic soda solution is to be determined, and a No. 2 
hydrometer is to he used, the level of the liquid reaching 
80°, the gravity of the liquid is 30° Tw. ; or, it multiplied 
by 5 and I'OOO be added, its true specific gravity, i.e. 1'1.5, 
will be obtained ; then the solution will be found to 
contain about 13 per cent, of caustic soda. 

Hydraulic Mean Depth.— The hydraulic mean depth 
of a liquid fiowing through a pipe is equal to the sectional 
area of liquid divided by the wetted perimeter. The 




the adjustable negative (or film-holder) frame D. This 
runs in rails like a rising and cross front, and is clamped 
when in proper position by the thumbscrews B and P, 
On the inner side of this is a box fitting closely inside 
the camera (film end). D is attached to C by the blocli 
H, which, resting upon the sides of A, holds everything 
firm and steady. At J is fitted the front of the enlarging 
camera, with the opening before the lens and a shallow 
frame P fitting closely around the kodak. (The kodak 
Q is, of course, supposed to be removed from its outel 
box.) Attached to the front by bellows E is a grooved 
frame K large enough to take a half-plate printing frame 
—that is, about Sin. by 6iin. Through this from the 
frame runs an iron or brass roa I, over which a staple U 
may he turned to clamp it and thus hold the frame K 
tightly in position. When a film is used it is fixed, ta 
keep it flat, between two pieces of glass and inserted in 
frame Vj the film towards K. A sheet of ground glass is 
then placed in the printing frame, the rough side of tht 
glass towards the operator, and the frame is placed in the 
grooves S of K, which is then extended almost to the full. 
D is next extended until the image thrown on the ground 
glass is nearly sharp. The fine focussing is done by 




Diagram of Hydraulic Mean Deptli. 



Enlarging with Focltet Kodak. 



sectional area of liquid is equal to ir^ (9 — sin.e). The 

wetted perimeter equals gjg-; .'. hydraulic mean depth = 
sectional area _ ir'le - sin, e) _ 90r (0 - sin. 9) . 
wetted perimeter ~ T^d ~ n B 

Knowing the diameter of the pipe and the depth of the 
liquid, the angle e may be found from the equation tan 

-~ =-=zrf.i where y equals ^/(.d-h) h. The hydraulic mean 

d 
depth- for pipes running full or halt full is j- 

Power Saw for Soft Stone.— The ordinary frame saw 
originally intended for sawing hard stone, and driven by 
power, is now used successfully for sawing Bath and other 
soft stones, including Beer stone and alabaster. The saw 
Is a long steel blade parallel in width and thickness, from 
10ft. to 12ft. long, 9 in. wide, and nearly iin. thick; it 
has coarse teeth, with a wide set for clearance ; it is 
easily fixed in the frame by tightening or keying up with 
a kind of wedge like that used tor the hard-stonesaw. 
When in motion the saw is fed with water, sufilcient 
only being used to keep the cut from clogging. The rate 
of speed (steam power) is from twenty-five to thirty 
strokes per minute, and a block of Bath stone 8 ft. long 
by 3 ft. deep can be cut through in from half an hour to 
three-quarters of an hour, aceordifig to the hardness of 
tlie stone. 

Staining Plaster Panels to Imitate Mabogany.— 
Cast plaster panels are made to match mahogany in 
the following manner. Procure three bottles, and place 
i pt. of methylated spirit in each. In No. 1 steep i oz. 
of gamboge ; in No. 2 1 oz. of dragon's blood ; and in 
No. 3 loz. of red sanders; this will give one shade of 
yellow and two shades of red. Mix the various shades 
with an equal bulk of polish ; apply with a camel-hair 
brush. Blend carefully together, building up the desired 
tones gradually by using the colours weak rather than 
by trying to get the exact tone by one application. 
Give the stains a thin coat of spirit varnish, then finish 
bright or dull as desired. 

Enlarging with Pocket Kodak.— A pocket kodak 
camera may be used for enlarging, as shown in the 
sketch. A is a baseboard about 15 in. long by 6i in. 
wide. The exact dimensions will depend upon the size 
of the camera and the focus of the lens. A slot is cut at 
B to take a tongue about 2 in. long. To this is fitted 



manipulating K. It is then clamped by U over L. Adjust 
finally in position by screws E and T. Now replace the 
ground glass with plain glass and place against it the fllmi 
side of the bromide paper or plate, and fill in the frame 
back. Cover the enlarging camera with a thick dark 
cloth and Burn some magnesium ribbon before D. The 
bromide paper is then developed like a contact print. 
If only one degree of enlargement is required, the 
bellows may be replaced by a rigid box. 

Extracting Salt from Sheepskin Rug.— Suppose 
it is required to treat a white sheepskin rug wnich, 
during damp weather, becomes covered with moisture. 
First remove any lining or edging that is on the skin, 
mix together bran and hot water, and with this mix- 
ture immediately cover the bottom of a wooden trough 
to a good thickness. Upon this place the skin with 
the wool folded inside. Then place on more bran, fold 
over again, more bran, and so on until the skin has 
been completely covered. Then pour on hot water 
untU the whole has been covered. Leave in this state 
for a day, when the salt will disappear. Wash in 
clean warm water, and dry in the shade, constantly 
beating or shaking it. When nearly dry, well rub it. 

Watches Stopping in One Position only,— When 
a watch will go in one position and stop in another, 
the fault can generally be traced to a defective pivot 
or pivot-hole i thus, if the watch be held so that the 
balance works on one pivot or in one pivot-hole, and 
the watch stops, that pivot or hole is probably damaged. 
The pivot may be bent, its end may be bruised and re- 
semble a " mushroom," or it may be too short to come 
through the jewel-hole and touch the endstone. The 
jewel-hole or endstone may be cracked. Other causes 
may be too much endshake to the balance ; the balance 
arms may touch the index curb pins or the hairspring 
stud ; the balance rim may toucn the balance cock or 
the watch-plate, or (in a Geneva) the centre wheel ; the 
hairspring may not be fiat, and may touch the balance 
arms or the balance cock ; the lever may touch the roller, 
or the 'scape wheel may touch the top or bottom of the 
slot in the cylinder. 

Preserving Berries.— In preserving winter berries 
immerse them in a fairly strong cold brine prepared! 
with ordinary table salt and water. The berries will 
keep in this way for a long time. Artificial berries are 
nearly always used for decorative purposes, because of 
the great dlfBculty in keeping the natural berries in 
an unshrivelled state. 



Cyclopaedia of Mechanics. 



69 



Making Waterproof Overalls or Oilskins.— 

Cnbleached calico is generally used for cheap oilskins, 
fine drill for better-class goods, and sometimes, but 
rai-ely, silk. Best linseed oil, with very little driers, 
is the most suitable dressing, and should take about two 
months to dry in a cool, airy place. Lampblack is the 
cheapest suitable black ; ivory black is better, but dearer. 
One pound to 21b. of lampblack may be used for 1 gal. 
of oil. It oil alone is used, 1 lb. to 1\ lb. of driers for 
1 gal. of oU may be added ; with lampblack, 2 lb. to 3 lb. 
of driers. Oclire is the only yellow pigment cheap 
enough to use. If the solution has to be made 
quickly, use plenty of driers, and hang the articles 
up to dry in a room artifloially heated. The solution 
should be laid on with a stiff brush or scraper in a 
thin layer, and the first coat must be allowed to become 
thoroughly dry before putting on a second i two or three 
coats wUl be required. The articles should be hung on 
sticks so that no two portions of the cloth touch. 
Boiled oil, coloured with ochre or lampblack, and a 
dash of driers is also used. It is recommended, in 
order to keep the oilskins from becoming stiff, that 
yeUow soap cut into shreds should be dissolTed lu 
the waterproofing paint, the proportions being loz. 
of soap to 3pt. of paint. A little beeswax dissolved 
In the paint is also used for the same purpose. A 
good black dressing is boUed oil and lampblack 1 qt., 
to which the white of five eggs and loz. of melted 



and slightly modified, but his form gives practically the 
same result. The next important formula proposed was 
that by Neville In the middle of the century, giving a 
different value for the coefficient e from that of the earlier 
experimenters. About this time Weisbach introduced hia 
well-known formula, which has been for the last thirty 
years so much used by hydraulic engineers in this 
country ; it is more complicated than any previous one, 
a varying coeflicient c being given, depending on the 
rate of the velocity. From 1850 to 1858 M. H. Darcy began 
In Prance a remarkable series of expel-iments on open 
channels and pipes, on a much larger scale than had 
previously been attempted. Darcy died in 1858, and his 
work was continued by his assistant, M. H. Bazin. The 
latest, and by far the most important, researches on the 
flow of water are due to Ganguillet and Kutter, of Berne, 
who published their researches in 1869 and 1870. These 
experimenters continued on the lines of Darcy and 
Bazin, and found that the Ohezy formula could be 
adapted to all cases, but that the value of the coefficient 
c varies under very many conditions instead of re- 
maining constant, as in the early form. Kutter estab- 
lished a series of " coefficients of roughness " which have 
been largely experimented upon in America, Germany, 
and England, and have been proved to be substantially 
acoarate. The following table shows more clearly the 
great difference between different formulae. CompaJison 
of formulae :— 



Pipes etjnnixg Full-disohaege in Cubic feet pee minute. . 













Inclination. 








Authority for Formula. 












































linSO 


1 in 150 


linSO 


1 in 250 


1 in 500 


1 in 100 


1 in 300 


1 in 750 


1 in 500 


1 in 1500 


1 in 1500 


Iin3000 


Chezy 

Eytelwein 


55 


32 


24S 


140 


99 


1253 


723 


457 


3170 


1830 


6043 


3563 


55 


32 


248 


140 


99 


1256 


725 


458 


3180 


1833 


5064 


3577 


Neville 


65 


35 


290 


157 


106 


1509 


826 


490 










Weisbaeh 


60 


34 


268 


143 


102 


13.57 


779 


478 


3431 


1910 


ma 


3676 


Box (hydraulics) 


51 


31 


240 


137 


97 


1230 


705 


443 










Darcy... 


61 


35 


286 


162 


113 


1485 


860. 


633 


3816 


2202 


6072 


4274 


Kutter 


41 


24 


225 


127 


90 


1133 


654 


414 


3340 


1925 


5750 


4020 


fianto Crimp 


51 


29 


259 


147 


103 


1472 


850 


633 


4181 


2375 


6891 


5033 




6-in. 
stoneware. 


12-in 


. stone\ 


Tare. 


24-in. brie 


k. 


4S-in. brick. 


72-in. brick. 



beeswax are added; give two coats, and allow each 
coat to di-y thoroughly before the next is applied. 
The drying will occupy quite two weeks. If the drying 
is not thorough the dressing will become sticky. If 
driers is used the oilskins are apt to crack. If the dress- 
ing is too thickly applied it will peel off where exposed 
to friction. 

Cross in Telescope of a Level. — The cross used 
in the telescope of a level is fixed in the eye end of 
the instrument, and just within the focus of the eye- 
piece, generally 1 in. from the eye end. But this 
varies according to the focal length of each eyepiece. 
The wires are taken from the spider, and directly 
laid over the diaphragm, to which they are attached. 
Experiments have been made with oth6r material, but 
the spider's web has proved the best for the purpose. The 
diaphragm is a ring of metal about iin. less in diameter 
than that of the tube into which it is inserted. Four 
screws which pierce through the tube hold it in position 
and serve for adjustment. The ring is bevelled in its 
inner circumference in order to provide a clear edge. 
The face to which the wires are fixed is marked off for 
the number and position of lines wanted ; then the web 
is stretched across in the marks made, and secured at 
each end by a drop of varnish. 

Comparison of Formulas for the Discharge of 
Water In Pipes.— The fundamental formula for* calcu- 
lating the velocity of water flowing through a pipe or 
channel, and for calculating the rate of discharge, is 
based on that of Chezy, a French engineer, who proposed 

in 1775 the formula 

V = l/'M' 

Where 
V = mean velocity of water in feet per second. 
R = hydraulic mean depth = area in sg. ft. of cross-section 

wetted perimeter m feet 
S = slope = i^cll^^tion o f water surfa ce 

length of pipe or channel 
c = a coefficient determined by experiment and fixed by 
Chezy at 93'4. This formula was further investigated 
by Eytelwein, a German experimenter, between 1814-15, 



New formulae proposed are either modifications of the 
Darcy and Bazin or Kutter forms, or, being dependent 
upon a single isolated experiment, are not entitled to 
any authority. 

Making Gold Wire Name Brooches.— The wire em- 
ployed for making American name brooches is a hard, 
tough brass of a gold colour, coated with gold. Various 
qualities are used, from a lightly gilded wire costing 
6s. ^er pound to a heavily gold-cased wire costing 6s. 
per ounce. The higher priced wires were first im- 
ported under the name of " American rolled gold " 
wire, but wire of an equal quality is now sold as 
" seamless gold plating wire." The gauges in general 
use for this purpose are Nos. 20, 21, and 22, round, and 
half-round for rings ,- also square and other shapes for 
bracelets, scarf pins, and ornamental articles. For name 
brooches. No. 20 is best suited to bold designs with flow- 
ing curves, and No. 21 for more compact forms, whilst 
No. 22 is only used in making names with small letters. 
But the condition of the wire also assists or retards the 
workman in working out his design. A hard wire is 
liable to break if bent sharply, and is also too springy to 
retain its shape after being bent ; whilst a wire that Is 
too soft, although easily bent whilst making a brooch, 
will as easily bend and crush out the design after being 
worn a few times. The tools for this class of work con- 
sist only of a pair of small round-nosed pliers, a pair of 
cutting pliers, and a small flne-cut file; these can be 
bought at any toolshop. The best designs and patterns 
fpr a novice are a few of the lower priced hrooches, pins, 
rings, and bracelets. It is advisable for the beginner to 
imitate first the simpler designs, such as for an initial 
scarf pin, in some cheap wire, until a certain proficiency 
has been attained. Hard-drawn copper wire of No. 20 
gauge will be found suitable for this purpose. The stem 
of the pin may be grooved spirally with one edge of the 
file, and pointed with the same tool. Twisted pins are 
made with square wire, held in one pair of pliers and 
twisted with another pair. "When proficiency has been 
attained in making scarf pins, a safety pin, or a brooch 
with a simple, short name, may be attempted. Skill in 
working the wire can be attained only by first prac- 
tising on copper or some other cheap material. 



70 



Cyclopaedia of Mechanics. 



Design for a Doll's Wooden Bedstead,— Figs. 

1 to 5 show the construction of a doll's bedstead. 
The size will vary according to reciuiremeuts ; any 



Fig. lis a general Tiew, Pig. 2 a side elevation, and Fig. 3 
is an end elevation showing the head. Figs, i and 5 
show joints, as has been said. 

Dustlng-on Process of Photography,— In the dust- 
ing-on process of photography, a glass plate is coated 
with a mixture of sugar and dextrine, and sensitised 
with bichromate of potash, the object being to pro- 
duce a film that will lose its tackiness or stickiness on 
exposure to light, the loss being greater in the parts 
covered by the denser portions of the negative. Thus a 
positive image can be obtained from a transparent 
positive only, or a reversed negative from a negative. 
The process is chiefly used in photo ceramic work, 
although it provides also a valuable method of intro- 
ducing fancy backgrounds into portraits, etc. After 
exposure (ten to thirty minutes in diffused light) 
some finely divided powder is brushed lightly over 
the sensitised surface, the powder adhering to the 
sticky portions. The development can therefore be 
controlled to almost any extent, and local intensi- 
fication and reduction can be carried on simiil- 
taneously. The process requires some experience in 
order to secure the best results, and the exposure 
is very difBcult to gauge; an actinometer is used, 
but atmospheric changes have great influence on the 
result. Prepare the following. Grape sugar, ioz. ; 
dextrine, i oz. ; bichromate of potash, i oz. ; water, 10 oz. 




Design for a Doll's Wooden Bedstead, 



kind of wood may be used. The posts and rails can 
be jointed by stub tenons and mortises as shown at 
Fig. 4, then glued together ; they may also be further 
secured by round-headed screws. The head- and foot- 
boards may be housed into the posts a little distance 
as shown at Pig. 5. This design, carried out on a larger 
scale, would make a neat little bedstead for a chud. 



"Whilst this solution Is filtering, clean some glass plates, 
coat them, and dry them slowly over a spirit la;°'P: 
Expose as above directed, and allow the ^ilate to stand 
aside and absorb some moisture from the air. Dust oyer 
the powder, and coat with collodion as a proteotlye 
varnish. A good washing in water serves to remove the 
bichromate salt. 



Cyclopaedia of Mechanics. 



71 



Hollowing Tlnplate.— A hollowing block cut prefer- 
ably from the trunk of an oak or beech tree will be 
required for hollowing tinplate ; a convenient Bize will 
be about 3ft. high and 2 ft. 6 in. in diameter. The 
holes on the top end are cut in varying depths and 
diameters with a small ad»e. If a variety of hollowed 
articles is to be worked, a set of block hammers will be 
required. These comprise a bullet-faced hammer for 
covers ; a -hammer with the faces curved to a greater 
radius than the first named for kettle bodies and similar 
work ; and one with the faces flaxter than either of the 
two former ones for canister bodies, etc. When working 
the metal, if a circle Is to be hollowed, place the metal 
80 that the edge of the circle is over a hole in the block 
of suitable depth, and then hollow it by delivering 
regularly with the hammer a series of blows first round 
the edge, and then in a series of concentric circles as 
far in towards the centre as may be desired. The work 
is then smoothed by again going over the hollowed part 
with light regular blows, or giving a series of radial 
strokes upon a planishing wheel. 'Wnen hollowing ovals, 
Buch as a kettle top, the sides of the oval do not require 
BO much hammering as the ends. If the shape is a rect- 
angle, or an oblong wi^h round corners, the corneis are 
the parts that require most working. Hollowed work in 
tinplate is usually executed in " tacks " of four or six 
discs or ovala, according to the thickness of metal used. 

Stephenson's Thermometer Screen.— The sketch 
■hows a Stephenson's thermometer screen, which 
consists of a box, either square or oblong, raised 1ft. 



is say 501b. per square inch, and the end of the 
piston an area of Isq. in., then 501b. of weight could 
be balanced. If one-third of the power is absorbed 
by the friction between the cylinder and the packing or 

gland, then 59jLl = 33-3 lb. equals the load that would 

be raised, the load including the weight of the piston 
and carriage, ear, or platform upon which the load to be 
lifted rests. If the area of the above piston end was 
equal to 100 sq. in., then 10" "SO x 2^ 3,333'3ii3. (which is 
the load piston, cage, etc.) that wovild be raised. 

Construction of Fireguard.— Fig. I shows the fire- 

fuard complete as it would stand round the fireplace, 
t should be of a size to fit against the centre of the 
mantelpiece jambs, and should stand about 30 in. high, 
though the height may be varied according to the posi- 
tion. The top rail should be of flat iron J in. wide by 
4 in. thick, and the bottom bar I in. by i in. These 
are bent as shown in ITig. 1, leaving the ends 12 in. 
long. This size may be either less or more accord- 
ing to the size of the room. The rails are drilled to 
receive the standard bars at intervals, leaving Sin. 
space between the bars. The bars of round iron iin. 




FiQ 1 FiQ 2 

Stephenson's Thermometer Screen. 

from the ground. The box may have louvred sides, that 
is, the sides may be made in a similar way to wooden 
shutters for windows, thus allowing air to penetrate, 
but keeping out the direct rays of the sun. But it is 
preferable to have the louvred side^ double, as illus- 
trated in section by Fig. 2, and not single louvred. In 
strong winds, direct draught on the damp cotton sur- 
rounding the hygrometer wet bulb would produce undue 
evaporation, and give a lower temperature than would 
be given by the same thermometer when standing in 
still air of the same temperature. The double louvre 
minimises the risk of direct draught, and keeps the en- 
closed air as still as possible. The box is open belotr and 
has a wood partition through the middle upon which 
the thei-mometers may be fixed. TheTroof is sloped, and 
may be painted or covered with tarred felt. The size 
of the box is notimportant ; but if it is made smallerthan 
3ft. by 24ft. by 2ft., it will be necessary to have a 
hinged door at each end through which to take the 
readings of the thermometers. 

Principles of Hydraulic Lifts, — Hydraulic lifts 
are of many forms and sizes, from the small dinner 
lift to the passenger or luggage elevator. The prin- 
ciples on which they work are very simple, and can 
be illustrated by a common syringe or squirt. If 
the nozzle of such an appliance is attached to a cock 
on a water pipe, a piece of ludiarubber tubing will 
do for making the connection, and the piston or 

8 lunger is pushed in as far as it will go before starting. 
In turning on the water, the piston will be forced 
outwards, and if stood or held upright a load or weight 
placed on the top would be raised. The weight of the 
load it would lilt would be in proportion to the pressure 
of the water in the main and the area of the end of 
the piston or plunger. If the pressure in the main 




Fig. a 



Construction of Fireguard. 



FIG. 2 



in diameter must be reduced at each end and then 
riveted into the rails (see section, Pig. 2). The 
back standard bar should be of flat iron Iin. by iin., 
with a round hole drilled through at 6 in. from the 
top to receive the screw on the plate, which is fixed 
to the mantelpiece, and to which the fireguard is 
secured by a thumb-nut (see Fig. 3). Another method 
of securing the guard to the mantelpiece is shown at 
Figs. 5 and 6. The top rail is turned down to form a 
hook, which falls into an iron eye on a plate fastened to 
the mantelpiece. The guard may be made more orna- 
mental by using an angle-h-on rail instead of flat iron 
for the bottom, and fixing on the front a brass ogee 
moulding (see Fig. i) and on the top rail a half-round 
brass moulding (see Figs. 2 and 8). The guard maybe 
painted dead black or any tint of enamel as individual 
taste may direct. 

Repairing Broken Cornice of Celling. — If the 

broken cornice is a fluted one, make a zino mould of 
it, using the good part of the cornice »* a pattern. 
Remove all loose plaster, dust with a stiff brush, and well 
wet the cavity with water. Mix to aproper consistency a 
sufficient quantity of Keene's plaster, beat it uptoathick 
paste, and apply with a trowel and sash tcol; gradually 
fashion the cornice by drawing the zinc mould back- 
wards and forwards until the new portion of the cornice 
lines with the old. If the cornice is an ornamental one, 
the broken part must be made good by a easting from a 
mould taken from the unbroken part of the cornice. 



72 



Cyclopsedia of Mechanics. 



Whitening a Discoloured Celling.— In whitening an 
old paper-lined ceiling that has gone a bad colour, 
clean off the ceiling and remove all loose paper; 
then apply a coat of size, whish may he made by dissolv- 
ing 6 oz. of glue In 6 pt. of water, and stirring in a hand- 
ful of plaster-of-Paris. To make a good job, line the 
ceiling with lining paper and butt the joints; for a 
strong job, catch-lap the joints. The ceiling may then 
be whitened in the ordinary way. If the ceiling is a 
very large one, use Irish moss instead of size witu the 
wliiting, as the moss will keep the joints from setting. 

An Easily-made Snow Plough.— For the construc- 
tion of the snow plough here illustrated, two elm slabs 
about oft. by 10 In. by IJin. are required; the planks 
might be longer and wider with advantage. Out one 
end of each plank as at A B (Fig. 1) ; then place it on 
the second, and draw a line along A B as a guide by 
which to cut the second. Place the planks edgeways, 
as in Fig. 2, and decide the- angle at which to fix them. 
A suitable angle will make the ends and E 2 ft. 6 in. 
or 3 ft. apart. Lay E ]? edgewaj's on the edge of C D 
at D at the proper angle, and mark the bevel at D. 
Then, having fixed OD edgeways, out down this bevel 
line with a saw. EP, when placed against this bevel, 
will now form the angle required, the outer edge 
being bevelled to a sharp edge. Two strong pieces of 
wood should then be cut to the length of the cross rails. 
Place all in position before nailing together, and mark 
with a pencil the ends of the rails on both planks. Then 
bore holes from the inside to the marks, and, when all is 
ready, nail the side pieces together with 3-in. or 4-in. 



side. Along the bottom of the central groove glue a 
strip of cork. Having laid the dead insect in the groove, 
a pin is pushed vertically through the centre of fts 
thorax down into the cork ; the height of the latter 
should be just sufficient to bring the wing above the edge 
of the side cork, and packing must be inserted where 
necessary to ensure this. An entomological pin, long and 
thin with a small head.is used. If the wings can be spread 
with a couple of sparrows'-tall or flight feathers fixed in 
a handle, all the better. Contact with lingers or tweezers 
or such like spoils the wings. Small slips of letter-writing 
paper are used as straps to hold the wings in their ex- 
tended position, a couple or more of ordinary pins being 
stuck through each strap, but not through the wings. 
Use plenty of straps to keep the wings extended ; putthe 
set insect aside for a week or so, remove the straps, and 
stick the sample inside a store box or case. Camphor 
enclosed with the specimens will preserve them from 
mites, which otherwise might spoil a valuable collection. 
In the busy insect season many adopt the system of 
leaving the killed insects to dry unset, so that they may 
be relaxed and set properly at leisure. Dry insects are 
easily relaxed by keeping them on damp sand for a few 
days, when they may be treated on the setting board 
precisely as if they had but just been killed. 

Table for Silvering Plate Glass.— The Illustration 
shows a hot table suitable for use in silvering glass; 
it has the middle slate removed. One -inch board 
should be used for the top of the table, the slate 
top S being IJin. thick. The inside should be lined 
with zinc to make it airtight, the zinc being brought 




FIG. 2 
An Easily-made Snow Flougli. 



Table for Silvering Plate Glass. 



wire nails. Place the rails in position, and nail from the 
outside through the holes already made. A piece of tin, 
such as a tin canister flattened out, will, it nailed on the 
front edge at D, ease the passage through the snow. A 
strong staple should be placed at each side, as at JP, for 
harnessing a pony or horse to draw the plough, when 
in use, some heavy logs or a box of stones should be tied 
on the plough to prevent it rising over the snow. 

Setting and Preserving Butterflies, etc.— Insects 
tp be preserved In a collection should be lulled separ- 
ately, in a wide-mouthed stoppered jar, at the bottom 
of which is cyanide of potassium covered with plaster- 
of-Paris. As soon as it is quite dead, remove the 
Insect from the bottle, catching hold of it by the middle 
— that is, where the legs join the body— and use a pair of 
tweezers, not fingers or anything as clumsy. Suitable 
tweezers can be bought at many shops, and can be made 
by bending double a strip of thin sheet steel or brass 
Jin. or j in. wide and 61n. or Sin. long tUlthetwo ends 
meet and form a delicate substitute for forefinger and 
thumb. The spring of the metal at the bend should keep 
the ends about I In. or lln. apart. The ends can be filed 
to a blunt point. Touch' the insect as little as possible, 
and always catch hold of it by the thorax. The wings 
and other par-ts of butterflies and moths are covered 
with minute feathers, which are rubbed off and de- 
faced at the slightest touch. The dead insect stiffens 
and dries up rapidly; therefore, have read.y a setting 
board, on which to hold it in position whilst drying. 
The setting board is made by gluing two strips of soft, 
smooth corkj each 9 in. by 1 in. by i in., to an under-piece 
of wood 9 in. by 2iin. by lln. The two cork strips are 
glued to the wood with tv i-in. groove between their 
longest edges, and the cork is slightly bevelled off on the 
outer edge. Insect setj;ing boards used by Continental 
naturalists are, however, quite flat; but English 
naturalists consider Insects to be spoilt if s6t flat. Of 
course, the larger the insect the wider will the board 
require to be. In the i-in. groove the body of the insect 
lies whilst its wings are extended over the cork on each 



over the side. The slate slab should be bedded in red- 
lead, all joints being filled with red-lead mixed with 
varnish. The table must be quite level. A blanket or 
piece of felt should be placed over the slate when in use, 
and made wet with water before the steam is used. 
Steam should be turned on gradually by a valve at 
I ; the hotter the table the quickerthe silver wUl deposit. 
The outlet pipe O lor steam is absolutely necessary, and 
could be regulated by a valve, as the confined steam 
would lift off the slate. The outlet pipe should be led to 
a convenient place so as not to interrupt a clear passage 
round the table. The pipe W in the bottom of the table 
is to let out the water formed by the condensing of the 
steam. The zinc is turned into the groove G, which is 
also for the bed of red lead. The glass to be silvered 
must be chemically clean, and whilst still wet from 
the washing it should be placed on the hot table and 
have a solution of gelatine or other mordant poured 
over it. Before this hardens, cover the glass with a 
saturated solution of nitrate of silver, and allow to 
remain untouched for about ten minutes. After 
wiping with a leather squeegee, again apply the silver 
nitrate solution, and complete the process by a final 
wiping with the squeegee. 

Polishing Cornelian Stones.— Perhaps the best way 
of polishing cornelian stones in the rough is first to grind 
them level on a suitable stone, or on a piece of York- 
shire grit obtained from a tombstone cutter. The stone 
must lie kept wet. When a level face is procured, 
grind out all the markings with emery powder, not 
too fine ; use this on a thick sheet of lead with water. 
On another sheet of lead grind with a finer emery all 
marks left by the first emery. Then grind with finest 
emery on another sheet of lead ; by this time there will 
be a dull polish. When no scratches are visible, polish 
with putty powder on a piece of felt or leather. Two 
things must De remembered : Do not stop grinding with 
one powder until all markings of a previous grinding 
are removed; and secondly, all the grindings must 
be wet. 



Cyclopaedia of Mechanics. 



73 



Spinning Copper.— Copper ia one of the easiest metals 
to spin in the lathe, because It is pliable and can be 
annealed straight off when it becomes hard. The tool must 
bear on the metal with firmneea, but it is best not to take 
too large feeds, but to mould the metal gradually. It is 
•of great advantage to hold a piece of hardwood against 
the back of the blank, particularly in the earlier stages. 
When the blank is first put on the chuck, or after it has 
been annealed, it feels very soft ahd yielding, but after 
a short time it gets harder, and it is not wise to work it 
too hard. The tool should not be moved from centre to 
circumference only ; that would tend to draw the metal 
away from the centre and make it thinner there and 
more liable to break. When the tool has travelled from 
the centre outwards, let it travel back again to the 
centre ; in this way the metal can be kept of the same 
thickness throughout. If the blank is fixed to the chuck 
by a screw through the centre, turn the chuck gra4ually 
during the spinning and anneal rather often. 

Bier Stand for a Mortuary.— The accompanying 
sketch shows the construction . of the frame of a 
mortuary bier stand. All the dimensions are clearly 
marked on the sketch, and when the top is boarded over 
with 1-in. boards (which should run across the frame), 




been heated in an oven. After the application, lay the 
carbon paper on an old newspaper and return to the 
oven to allow the mixture to soak in. After about halt 
an hour's heating any excess of fluid may be removed 
with a cotton rag ; the paper will be fit for use on cooling. 

Making Opalines In preparing opalines, immerse 

a photographic print in a 5-per-eent. solution of gela- 
tine. Warm the glass, and pour on it in a pool a por- 
tion of the gelatine solution; immediately lay the, 
print, face down, upon this, and squeeze out any air 
Dells. The glasses are generally edged round inside 
with a rim of gold paint. The prints should be cut 
slightly smaller than the glasses, and be just large 
enough to cover the rim. Before the print dries a 
piece of waterproof paper is mounted over the back. 
Finally, the strut is afBied with glue. 

Air Pump for Blowlamp An air pump for a blow- 
lamp, and particularly suitable for the apparatus 
described on p. 151, may be made from brass tube lin. 
in diameter and Bin. long. Take a thick circular 
41sc'of brass of the same diameter as the tube, and drill 
a conical opening in the side, and also a cross channel 
to join it as at S ; then braze the drilled disc on the 
end of the tube. File away the surplus spelter, and 
with emery and oil grind the conical opening true, so 
that when the metal ball shown is dropped in it will . 





< 


1 


L 




Bi ;!llill 




1 j 
j 


' 1 










H 




W' 



Bier Stand for a Mortuary. 



Air Pump for Blowlamp. 



overhanging at the sides and end about an inch, the 
stand will be complete. The stands may be made of deal, 
but oak is preferable, though of course more expensive. 

Particulars of Microscope Slides.- Some Jnicroscope 
cells are made by painting rings of marine glue upon a 
elide, and repeating this until the cell is deep enough. 
Other cells are formed by cementing pieces of plate glass 
(with the interior removed) to the slides; whilst others, 
known as " sunk cells," are formed by grinding out a 
hollow in the sjide. Others, again, are known as "tube 
<!ells," being formed by cementing a section of round or 
rectangular glass tube to the slide glass. These may be 
of any size. There are also "buOt-up cells," made by 
cementing separate pieces of glass together. 

Making Carbon Paper.— In preparing black carbon 
paper either of the two following compositions may be 
used, (a.) Finest lampblack 5 parts, olive oil 5 parts, eerasin 
wax 1 part, and pfetroleum ether 10 parts. (6) Lampblack 
5 parts, eerasin wax 6 parts, olive oil 5 parts, and petroleum 
«ther 15 parts. The lampblack and oil are ground 
together in a mortar, transferred to a small dish or 
pan and slightly heated, and the eerasin wax added ; 
when tbe latter has thoroughly melted, well stir the 
mixture, remove it to a safe place, and while still 
warm add the petroleum ether. For a bluish-black 
shade, add a little Prussian blue. The mixture, whUe 
■warm, should be applied with a brush to paper that haa 



completely close the passage. If any difBculty is experi- 
enced in making the ball fit air-tight, line the cone with 
thin leather ; the ball will then act satisfactorily. C is a 
plug of leather well soaked in oU, and attached to the 
plunger rod by means of a small nut as shown. When 
In use, the back pressure exerted on the lower end of 
the plug causes it to expand on the down stroke, and so 
closely fit the tube that all the air in it is forced through 
the outlet D. On the upward stroke commencing the 
ball closes down the hole at D, and air passes the sides of 
the plunger as it is drawn upwards. A screwed cap B 
made to fit the barrel completes the pump. 

Cementing Joints Round Cooking Ranges. — A 

cement that will not crumble and break away from 
joints in a cooking range and from around the front 
edges of range covings cannot be obtained. The heat 
appears to affect the cement, but the real cause is the 
expansion and contraction of the range parts when 
heating and cooling. A slow-setting cement might be 
used, so that when the fire is lighted the range parts 
and cement may accommodate themselves to each 
other. If care is taken to keep the joint very small 
common glaziers' putty could be used ; this answers well, 
as it eventually hardens with the heat. But better Btill 
will be to have the stone jambs tight up or overlapping 
the edges of the covings ; or provide a moulded edge up 
each side and across the top of the range to overlap 
the jambs and frieze. 



74 



Cyclopsedia of Mechanics. 



The Pulsometer.— The illustration shows a sectional 
elevation of a pulsometer, which is an appliance for 
raising water hy the alternate pressure and condensation 
of steam. To describe the pai-ts, K is a pipe from a boiler 
containing steam under pressure. The gunmetal spheri- 
cal valTe is free to move and to alternately cover the 
necks I and J. The latter form the upper parts of the 
chambers A A, into which water passes througnthe valves 
E E from the suction pipe F. 6 G are doors for access to 
the valves E E for repairs or other attention. Near the 
bottom ends of A A are side outlets, as shown by the 
dotted circles, covered by the valves r r, also shown 'by 
dotted lines, opening into a chamber with which are con- 
nected the air vessel B and the outlet branch D, to which 
the delivery pipe is attached. The action is as follows. 
The pump is first charged with water through plug-holes 




Sectional Elevation of Pulsometer, 



provided for the purpose, and then steam is turned on 
at K. This presses on the water on the right hand 
chamber A (which is not covered by the spherical valve), 
and forces it, as shown by the arrows, through the right- 
hand valve P and up the delivery pipe. The steam in 
the right-hand chamber A then condenses, and causes 
the spuerioal valve to roll over and cover the neck j, and 
also creates a vacuum, which is again fllloA with water 
through the right-hand valve E from the suction pipe 0. 
When the valve has rolled over j, the steam passes 
through the open neck I and presses on the water in the 
left-hand chamber A, forcing it through the dotted left- 
hand valve ]? into the delivery chamber. When the left- 
hand chamberAisnearly empty, the valve is again pulled 
back by the condensation of the steam in the chamber, 
which again fills with water during the time the other 
chamber is being emptied, and these actions continue 
as long as steam under efficient pressure is supplied. As 
water will not rise in a vacuum beyond a certain height, 
a pulsometer should not be fixed more than about 15 ft. 



or 20 ft. above the water to be raised, although theo- 
retically the limit Is a little more than 30 ft. The pump ca» 
be slung on chain s in a well or sump, so that there is very 
little trouble in fixing it, or lowering it when necessary 
for keeping within a working distance of the water. 
The height to which a pulsometer will raise water 
depends on the pressure of steam in the boiler, which i» 
used In conjunction with the apparatus. 

Making Typewriter Inks.— One of the most popular 
recipes for ink for typewriter ribbons is as follows. 
Melt some petrolatum, having a high boiling point, on 
a water bath. Petrolatum is a soft hydrocarbon obtained 
from the residues left after the distillation of lighter 
oUs from crude petroleum, or it may be deposited by the 
latter on standing ; its commoner name is vaseline. In- 
corporate as much lampblack or powdered dropblack as 
the petrolatum will take up without becoming granular. 
When the mixture is partly cool, dissolve It, a little at & 
time, in a mixture of equal parts of petroleum, benzine, 
and rectified oil of turpentine. Eegulate the quantity 
of the latter solvents to produce a solution of the con- 
sistency of fresh oil paint. Try on one end of the ribbon 
and, if too thin, add wax ; if too faint, add colour ; if 
too hard, add vaseline. Apply to the ribbon and brush 
off the excess. Many typewriter '" ks have glycerine, a 
very undesirable Ingredient, as the rehlclefor the colour- 
ing matter. The following recipes are typical of the com. 
position of such Inks. (1) Dissolve i oz. of aniline dye in 
4 oz. of glycerine, and add 2 oz. of alcohol and 2 oz. of 
water. (2) Dissolve 1 part (by weight) of powdered 
aniline dye in 6 parts of glycerine, and add 3 parts 
of soft soap. Warm until the soap dissolves and 
well mix. (3) Dissolve i oz. of aniline dye in 15 il. oz. of 
alcohol, and add 15 fl. oz. of glycerine. (4) A good ink is 
made by dissolving 1 part of aniline dye (soluble in 
oU) j«» 6 or 8 parts of oil of cloves ; gentle heat 
assists the solution. The aniline dye in these four 
recipes may be of any smtable colour ; black and violet 
are perhaps the most serviceable. Another method of 
making a black ink is to grind 1 part of gas black 
with 5 parts of oil of cloves. All inks containing 
aniline colouring matter and glycerine are copying 
inks. Two other recipes for copying inks are here 
given. (1) Grind 1 part (by weight) of suitable ani- 
line colouring matter with 6 parts of glycerine. (2> 
Dissolve, by the aid of heat, 1 oz. of transparent soap in 
a mixture of 4fl. oz. of glycerine and 12a. oz. of water; , 
mix with a solution of a sufficient' quantity of aniline 
dye in 24 fl. oz. of alcohol. If the ink is too thin, add soap. 
The unsatisfactory results given by home-made type, 
writer inks appear to be caused by the use of glycerine 
as one of the Ingredients, according to Prof. Shuttle- 
worth. The hygroscopic properties of glycerine make It 
an undesirable ingredient, and the addition of glucose, 
soap, alcohol, or water does not Improve matters. 
Vaseline, with or without the addition of wax, gives 
better results, but its consistence is appreciably affected 
by temperature. Prof. Shuttleworth proposes castor oil 
as a more suitable medium ; the colouring matter maybe 
any of the salts of the aniline series, and of these methyl 
violet IS practically soluble in the oil mentioned. In 
preparing the ink, triturate the powdered colour with the 
oil in the mortar, the work being facilitated by the 
addition of a very little alcohol A suitable formula 
for such an ink is that of Higgins. Castor oil, 4 oz. ; 
carbolic acid, 1 oz. ; oil of cassia, 1 oz. ; suitable aniline 
colour, loz. Printing inks may be modified for service 
In the typewriter by adding vaseline to make them non- 
drying on the ribbon ; if it is found that they are too 
soft, add wax also. 

Fog on Photographic Dry Plates. — If light 
reaches a dry plate by any other way than through 
the lens when the plate is exposed in the camera, the 
result is fog ; that is, the sensitiveness of the plate is 
destroyed, and development produces black patches of 
greater or less intensity according to the amount of 
light that has accidentally fallen on the plate. This 
fog may be due to defective slides, to cracks in the 
camera, to leakages of outside light into the dark room, 
or to an unsafe lamp. In a score of other ways, all of 
which may be classed under careless or faulty handling 
of the plates during their journey from the maker's box 
to the developing dish, light may reach the sensitive plate 
and cause fog. 

Lead-light Glazing.— As a cement for fixing lead lights 
to steel frames, the following preparation will probably 
give satisfaction. . Mix liquid glue with a sufficient 
quantity of wood ashes to form a thick mass ; the ashes 
should be added in small quantities to the glue (while 
boiling) , and constantly stirred. A sort of mastic is then 
obtained, which, applied hot to the glass and metal, fixes 
the two firmly together. A good hard stopping can b* 
made of fine litharge, 2 parts; white lead, 1 parti 
copal varnish, 1 part ; boiled linseed oil, 8 parts ; the 
whole is well triturated together. Lead glazing may be 
fixed in either wood or metal frames. 



Cyclopasdia of Mechanics. 



75r 



Making Triad Pictures.— A triad picture is simply 
three pictures in one; from a standpoint exactly in 
front of It a certain view, represented by X (Pis. 1), is 
seen. Prom a point a little to the right-hand side is seen 
a totally different view, represented by T (Pig. 2) ; wUle 
movement to the left discloses a third picture Z (Pig. 3). 
The construction is very simple. Pirst get three pic- 
tures and select the central one. For the purpose of 
description, suppose it to be 13 in. wide ; the height is 



tures. Divide it into thirty-seven parts, and mark each 
etc. (Pig. 7). Now, with a very sharp knife 



A 



X , 



cut off the central picture the slip marked -j (Pig. 4) , and 



paste it on the division marked j (Pig. 7) . 

Z or left-hand picture and cut off' the slip marked -j 



Next take the 
z 




Fics.3 



Fig. I 



Fig. 2 



m 



m? 



i 



Z' z 
7 8 

nil 



m 

'z 'z 

10 II 

m 



Fig. 6 




Fig. 4'. 



iii|Piy|P'|piip|w 


m 


Y yfy! Y y Y Y Y y|y Y 


Y 


t 2I3I 4 5] 6 Tja 9 10' II 


IB 




i 



Fig. 5, 



plf 


||l" 


111. 


ijpi 


jP 


IIP 


Wp 


fp|iii 


P 


iP" 


III"' 


r 


w 


\f 


f 


f* 


jP 


f 


|||l 


fW 


IIP" 


P 


W 


w 


pp 


p 


P 


|)|l||l|lipi»||ll|||Plipi 


A A 


A 


A 


A 


A 


A 


A, A 


A A 


A, 


A 


A 


A 


A 


A 


A 


A 


A. 


A 


A 


A A 


A 


A 


A 


A 


A 


A 


A 


A 


A 


A 


A 


A 


A 


1 2 

id 


3, 

A 


4 

d 


5, 


i 


i 


H 


10 II 

M 


2 


i 


i 


2 


i 


17, 

4 


18 

i 


19, 

i 


20 

i 


21 

i 


22 


23 24 

iil 


25 

i 


2 


27 

i 


28 

i 


3 


II 


i 


^334 35 


36 

J 


37 



FIG. 7 



llppllll}pllll 

XZYXZYXZYJ(2YXZYXZYXZYXZYlX Z.Y Xi Z Y X Z Y X Z Y )< 

I I, I 2 2 2 3 3 3 4 4 4 5 5, 5 61, 6 6 r 7 7. 8. S 81^ 9 9 91 10 ICI lOl II II II, I2j 12, 12, 1'S.. 

iiLiilJ:i .iiiyyjia^^ 



Fig. 8 



x^ 



■"t 



Fig. 9 



Making Triad Pictures. 




not material at present. On the back of the picture 
rule pencil lines, dividing it into thirteen divisions, 

each lin. wide, and mark these divisions ^, 2, ?, and 

1 2 o 
so on, as shown on Pig. 4. Next take the picture repre- 
sented by T (Pig. 2) . Suppose it to be 12 in. wide ; on the 
hack rule pencil lines, dividing it into twelve divisions, 

V T V 

and mark the divisions =-, i, -j, and so on, as shown 
1 2 o 

on Fig. 5. Space the third picture (also 12 in. wide) into 

twelve divisions, and mark each -, ^, -, etc., to Fig. 6. 

Next t?,ke a sheet of paper (lining wall paper will do), 
37 in. long, and in width equal to the height of the iiie- 



(Pig, 6), and paste it on .f (Fig. 7). Then off the T or 
2 

right-hand picture cut the slip y (Pig. 5) and paste it on 
3 (Pig. 7). Now return to the X picture, and cut off the 
slip ^(Pig. 4) and paste it on ^ (Pig. 7), and so on, until 

all the slips are pasted in the order shown on Pig. a. 
Now fold the combined picture on a piece of miUboard 
slightly larger than the central picture, paste down the 
first strip X' (Fig. 8), paste Z' and ¥' back to back, secure 
X^ close to the first strip, put 7? and Y' back to back, and 
so on (see Fig. 9). It the pictures are comparatively 
narrow, say 9 in. or less from top to bottom, do not cut 



^6 



Cyclopaedia of Mechanics. 



the centre one but paste it on a sheet of card, which 
should be 1 In. larger all round than the picture. Now 
glue a 1-ln. by 1-in. wood slip, neatly mitred at the 
angles, round the edges of a sheet of stout millboard, 
meike saw cuts iin, long and lin. apart in the top and 
bottom pieces, and Bx the frame round the picture. 
Paste the other pictures on paper having i-in. margins 
at the top and bottom. Cut them into 1-in. strips, paste 
corresponding strips back to back, run the brush along 
the proper edge of the connected strips, and iix the ends 
Into the i-in. saw cuts. If the centre picture is wider 
than the others, the height of the upstanding strips will 
be less than the width of the centre picture strips ; when 
■uprights and flat strips are of equal width, as In Fig. 9, 
shadows are apt to Interrupt the side views. Spaces as 
X' in Pig. 9, lin. wide, with uprights T* Jin. high, will 
suit a centre picture 15 in. wide, and two others 104 in. 
wide, or one 10 in. wide, two 63 in. wide, etc. ; dimensions 
respectively of lin. ana J in. suit a centre picture 15 in., 
and two other 7 in. ; and dimensions of } In. and i in. suit 
a centre picture 12 in., and two others 7i in. Oleographs 
and photographic enlargements make good triad pic- 
tures. Triad signboards having worded announcements 
ai-e made as in the section (Fig. 10) with wedge-shaped 
pieces having 1-in. sides and i-in. base. Paint these 
«ame as gi'ound, and put a letter in each division. 

The Manufacture of Artificial Gems.— As early as 
1837 Gaudin made artificial rubles by heating ammonia, 
alumina, and potash by means of an oxy-hydrogen blow- 
pipe; the Intense heat volatilised the potash and 
alumina, afterwards producing crystals in rhombohedral 
forms identical with those of the natural stone, and 
liaving the same specific gravity and hardness. Methods 
of producing crystals of corundum, ruby, sapphire, etc., 
were discovered about 1858, but both these and Gaudin'a 
processes had but little commercial value, the great 
expense precluding their adoption. Until quite recently, 
the only artificial gems known to commerce were 
coloured glass, and, in some cases, wax preparations 
backed with silver or a mercury amalgam. Wow, how- 
ever, the chemist can produce imitations that, in lustre 
.and hardness, equal the real or found gems; perhaps 
" imitation " is not the correct word, as the composition 
of both manufactured and found stones is supposed to 
be the same. Sometimes it is quite impossible to dis- 
tinguish between the two kinds of gems, although 
generally examination under the microscope discloses 
some difference. As seen through a microscope, natural 
rubies contain minute cracks which indicate the lines of 
cleavage ; the artificial gem shows very minute bubbles 
or gas holes. Analysis has proved that the sapphire is pure 
alumina, that is, oxide of aAuminium (AI3O3) . This is found 
in the form of a white powder fusible at high tempera- 
tures only. The colour of a sapphire is supposed to be 
4ue to the presence of chrome, and is dichroitic, that is, 
it varies with the point of observation ; thus, it is 
«uecessfully imitated only with difficulty. M. Sidot, the 
French chemist, accidentally discovered a method of 
producing gems that possessed dibhroitio properties. 
His method is to heat an Iron pot 'jo dark red and to 
place in it 4oz. of superphosphate of lime ; this is brought 
to the same heat and stirred with an iron rod, being 
then converted to crystallised pyrophosphate, which, 
on being further heated, becomes a fluid resembling 
molten glass. It is supposed that in this state a part of 
the phosphoric acid is changed to a tribasic phosphate. 
The fused mass is stirred continuously until it is quite 
transparent and free from bubbles, when It is transferred 
to another pot and kept at a white heat for two hours, 
the, stii-ring being kept up all the time. After standing 
for an hour, it is poured on to a metallic surface and 
allowed to cool slowly until as soft as putty, when it is 
put on plate glass. When cold, a number of sjones 
almost equal to i the genuine sapphire may be cut from 
the plate. Another formula is : Smelt a mixture of i oz. 
of oxide of aluminium and 4oz. of red lead (PbsOJ, and 
stir in lOgr. of bichromate of potassium (KoCrsO?) and 
17 gr. of oxide of cobaltum (CoO). When cold, stones 
may be cut that are as hard, if not quite so brilliant, 
as the genuine ones. The ruby, also, is oxide of alu- 
minium coloured by chrome. Crystals of the rose- 
coloured ruby may be produced by melting together 
aluminium oxide and powdered silica, Tvith the ad- 
dition of fluoride of barium to form a flux, and then 
adding a trace of bichromate of potassium; 5001b. 
of these ingredients, after perhaps a week's fusion, 
will produce rubles of 5 or 6 carats which may vary much 
in colour, running through all the shades of bluish 
sapphire and rose to the deep colour of the so-called 
pigeon-blood ruby. Ordinary borax fused with a little 
■chromium oxide for a week or so produces large ruby 
crystals; but 2001b. of ingredients may be required to 
obtain even two or three gems of any marketable value. 
One method of making artificial rubies is to smelt a 
mixture of 4oz. of oxide of aluminium and4oz. of red 
lead, and add from 7gr. to 16 gr. of blohromate of 
potasBium. Ifatural emeralds are a combinatiou of the 



rare element beryllium or gluciuum with silicon ; chrome 
gives the colour. Beryllium is too expensive for use in 
producing imitations, so oxide of aluminium is used, 
i OZ. of this being smelted with 4 oz. of reii lead, to 
which from 8 gr. to 12 gr. of uranate of sodium (Na^TJaO?) 
have been added. Hautefeuille & Perry, the French 
chemists, produce some beautiful emerald crystals 
by fusing silica, alumina, glucina, and a trace of 
chromium oxide with acid molybdate of lithia. After 
a fusion of fifteen days some very small crystals, having 
all the mineralogical and physical characters of the 
natural emerald, may be obtained. The longer the 
fusion the larger are the crystals. Emeralds and other 
gems nave been produced from gas retort refuse by a 
method discovered by Mr. Srevllle Williams, F.E.8.. who 
modelled an emerald composed of from 67 to 68 per cent, 
of silica, 15 to 18 per cent, of alumina, 12 to 14 per cent, 
of glucina, and traces of magnesia, carbon, and car- 
bonate of lime. The colour was an intense green, due, it 
is believed, to the presence of sesquioxide of chromium. 
Imitations of the amethyst, topaz, etc., have been 
made very successfully by Donault Wieland, of Paris, 
whose method of preparing "Parisian diamonds" or 
" Alaska diamonds is to smelt a mixture of 65 per cent, 
of pulverised crystal quartz, 20 per cent, of i-ed lead, 
8 per cent, of pure carbonate of potash, 5 per cent, of 
boric acid, and 2 per cent, of white arsenic. The brilliancy 
of the resultant stone depends principally on the purity ' 
of the red lead and of the carbonate of soda. 

Frinclples of Sewing Machines.— The principle 
of the lockstitch sewing machine is, roughly speak- 
ing, as follows. The needle descends to the bottom 
of its stroke, and simultaneously the shuttle slides, 
vibrates, or oscillates as far as the end of its backward 
movement. Continuing the movement of the balance 
wheel, the needle begins to rise, and the shuttle 
immediately after begins to move forwai-d. As the 
needle rises the material through which it is passing 
holds the needle cotton long enough to cause it to loop 
out behind the eye of the needle under the needle- 
plate. The shuttle, still moving forward, enters this 
loop and passes through it, the necessary amount of 
slack cotton being si^pplied either by the " time " of the 
needle-bar or by the check or take-up lever, according 
to the style of the machine. By the "time " of the needle- 
bar is meant the movement which is caused by a cam 
on the bar, causing it to descend the second time after it 
has risen sufficiently to throw out its loop and to allow 
the shuttle point to enter it. This descent throws off 
enough slack cotton to pass over the body of the shuttle 
without causing any strain on the cotton, and as soon 
as the shuttle has passed through the loop the needle- 
bar rises to its highest point and draws up the cotton 
into the material being sewn and the bottom or shuttle 
cotton with it, completing its stitch. Under the material 
and under the needle-plate is a teed dog which rises just 
before the needle has reached its highest point, and, 
moving back, carries the material with it the required 
distance and sinks below the needle-plate before the 
needle enters the work again. If the machine is a 
rotary hook machine, the hook, instead of sliding or 
oscillating backwards, continues to revolve, and is so 
arranged that when the needle is at the lowest part of its 
movement, the point of the hook is a little behind It, 

fenerally about Vjin., a little more or less according to 
he style of the machine. The main points to remember 
are ; (a) Short groove of needle is always toward the 
shuttle or hook, (b) When the needle is rising and the 
point of the shuttle is just level with ' it, the eye of 
the needle must be iVin. or more below the shuttle 
point, (c) The shuttle must not start to come forward 
before the needle begins to rise, (d) The feed must carry 
the material while the needle is well out of the work. 
(e) See that the shuttle point is sharp, and that the 
shuttle driver wherever it touches the shuttle is per- 
fectly smooth, and that all points over which the cotton 
runs are also smooth. The movements of chalnstitoh 
machines are similar generally to the rotary hook 
lockstitch machine, but the hook having picked up the 
needle cotton does not drop or allow it to slip off un^iil it 
has picked the second needle loop. It is very essential 
in chainstitch machiues to have the right make of 
needles, as poor needles cause endless trouble. The 
short gi'oove of the needle is again nearest the hook, and 
the hook should pass as near the needle as possible 
without touching. See that the hook is perfectly smooth, 
and in putting together such machines do not alter in 
the slightest the shape of this hook. 

Removing Rust Marks from Wood.— In re-palnting 
wooden structures disfigured by the marks caused by 
iron nails having turned rusty, first rub out the rust 
marks with sandpaper, getting as much i-ust as possible 
off the nail heads ; then with a small brush worn down 
to a stump rub well in around each nail head some good 
oil varnish. When quite dry, apply the paint. The 
above method will check the rust to a great extent, but' 
it will still form in the holes against the wood. 



Cyclopaedia of Mechanics. 



77 



Testing Gravel for Gold.— In testing a hard rocky 
grayel for gold, first finely powder a sample of the gravel, 
moisten it In a tall cylinder with water, and pass chlorine 
gas through it, whereby Soluble chloride of gold is formed. 
After treating with chlorine the gravel should be washed 
with hot water, the solution collected in a dish, boiled to 
expel the chlorine, and then heated with solution of 
ferrous sulphate. If gold is present it will separate as a 
fine brown powder. Another method is to take, sajf, i lb. 
of the powdered gravel, mix it with litharge (oxide of 
lead) and flour or cream of tartar, and heat it in a 
crucible in a furnace. The litharge is reduced by the 
flour or crealm of tartar forming metallic lead, which 
melts and, as it passes through the gravel, takes the gold 
with it to the bottom of the Crucible. After heating, the 
crucible is broken open and the button of metallic lead 
is removed. It is first roasted in a dish in a muffle 
furnace to get rid of the greater portion of the lead as 
oxide ; the oxidation is then finished on a bone-ash 
cupel, which absorbs the oxide of lead formed, leaving, at 
the end of the operation, a button of metallic gold, 
providing that metal was present in the gravel. 

Water-tight Sliding Door.— The opening to which a 
sliding water-tight door is to be fitted in a ship should 
have an angle frame all round at the edges of the plate 
to stiffen up the plating. This angle is on the side of the 
plate opposite the door. The sketch shows the general 
construction of a slidin g watertight door at the en d which 
takes the screw for sliding the door open. A and D are 
the sides and top of the cast-iron frame which forms the 



and tne topping. The bottoming, which is composed of 
slag, clinkers, etc.. Is mixed with a hot composition of 
gas-tar boiled in a cauldron, a little pitch and resin 
being added. Before being used, the materials must he- 
allowed time to become thoroughly incorporated with 
the tar. The formation level being ready, a thickness of 
2 in. of this bottoming is laid and well rolled. The top- 
layer, 1 in. in thickness, is now laid on this and well 
rolled. The topping differs from the bottoming only in 
the smaller and finer quality of the materials which, in- 
the case of topping, are mixed with the tar. The surface 
is now flooded with the tar composition in a boiling- 
condition, and, whilst wet, is blinded -with clean white 
sand or fine granite dust. A footpath of -this kind lasts- 
a long time without requiring any repairs worth men- 
tioning. Inequalities and bad patches must be cut out 
as soon as they occur, and new material well rammed in. 
Every two or three years, according to the character 
and extent of the traffic, a fresh top should be laid over- 
and blinded. These footpaths will, however, last usually 
six or seven years -without requiring absolute renewal. 

Cleaning and Mounting Antlers.— Below are given. 

instructions on cleaning and mounting a pair of stag's- 
antlers. Well wash and scrub the antlers with warm water 
and soap. Thoroughly dr.y them with a cloth Or towel, 
then give another smart rubbing with a perfectly dry 
cloth to remove some of the dulness from the sharp edges- 



o4-F 





Water-tight Sliding Door. 



Cleaning and Mounting Antlers. 



bed for the door to slide on. B shows pieces of plate, 
generally about Sin. broad, which form the back sliding 
surface. The door itself (C) is a casting. Across the 
centre and bottom of this is a web, as well as that shown 
at the top. These webs are solely for stiffening the door. 
A hole is made through at the centre to allow the door to 
travel up the screw when the door is being opened. The 
centre of the screw is usually kept about 6 in. from the 
bulkhead, and it and the gearing rods are supported, by- 
cast-iron brackets. When the geai-ing has to be angled, 
bevel wheels are used about 6 in. in diameter, wi^h thirty 
teeth of l-in. pitch. The gearing rods are usually 
about 11 in. in diameter. 

Proportions for a Compensation Pendulum.- A zinc 

and steel compensation pendulum for a regulator clock 
having a dead-beat escapement is of fairly simple con- 
struction. For a seconds pendulum the central rod 
is of steel, •^t in. thick, and measures 45 in. from the 
bottom of the thread for the rating nut to the point 
of suspension. Over this rod, and resting on the rating 
nut, is a zinc tube 26 in. long andfrom Jiu. to -j^ in. thick. 
This tube slides freely over the rod. Outside the zinc 
tube, and depending from its top end, is an outer steel 
tube (bicycle tube) 23 in. Ibng. At its lower end an 
outside collar is fixed, on which the bob rests. This is 
of lead, cast with a central hole having a shoulder in its 
centre. The upper part of the hole just trees the steel 
tube, and the shoulder rests on the collar. The lower 
part of the hole is large enough to clear the collar. 
Thus the bob is supported at its centre and expands 
as much up as down. Its length is 9 in. and its shape 
cylindrical. For a 14-lb. bob 21 in. diameter will be suit- 
able i for a 17-lb. bob 2J in. wiU do. 

Laying Tar Footpaths. — Tar footpaths are inex- 
pensive as compared with fiagging, etc., and if properly 
laid, water will not soak into them, nor will the heat of the 
sun melt the tar. It is laid in two layers— the bottoming 



and iirominences. The antlers can be mounted by one of 
the following methods. Fig. 1 shows how, by cutting a 
piece off the back of the antler, it may be fixed to the 
mount by means of a screw passing through a hole 
previously di-illed in the antler. Fig. 2 shows an arti 
ncial forehead of wood , with short processes or projections- 
upo'n which the antlers rest, being screwed from the 
back. Another method is to drill a large hole length- 
wise into the antler from the base, and in this hole 
to place a dowel (see Fig. 3), by means of which the 
antler may be fixed as in Figs. I or 2. Beslgns of shields, 
or mounts are shown by Figs, i to 7. To make these, 
double a piece of paper, draw half the shield as shown, 
and cut out through both pieces of paper. Flatten 
out the paper and mark round on the wood with a 
• pencil. The mounts can be made of oak, mahogany, 
or walnut, the first-named for preference. Ebony or 
ebonised wood is rather too gloomy, though often used. 

Gilding Steel Pins.— Highly polished steel pins, free 
from grease and oil, may be gilded in an electro-gilding 
solution of gold cyanide. When a quantity of pins ia 
required, they may be gilded in dozens at a time if 
suspended in the solution in a basket of platinum gauze, 
which must be shaken whilst the gilding process is 
going on. Any gold deposited on the platinum may be 
afterwards dissolved off in the gilding solution without 
doing it any injury. The pins are scratch-brushed and 
polished in the usual manner. This method is applic- 
able to all small steel articles. 

Varnish for Walnut Gunstock.— A walnut gunstock 
may be coated with a very bright varnish made accord- 
ing to the following recipe. Take 4 oz. of best orange 
shellac, 4 oz. of gum sandarach, 2 oz. of gum benzoin, 
I oz. of Venice turpentine, one pennyworth of carap4ior, 
and 1 pt. of methylated spirit frequently agitate, and 
carefully strain through muslin. The varnish should be 
applied with a camel-hair brush in a warm room. 



78 



Cyclopsedia of Mechanics. 



How to Make Fbotographlc Silhouettes. — In 

making photographic silhouettes, as the exposure re- 
quired is BO much less than that necessary for an 
ordinai-y portrait, a slow lens can he used. Stretch a 
sheet across an open doorway where it can be well 
Illuminated from without, and set the camera up in the 
room, the figure being close against the sheet. BemoTe 
from the room any articles likely to throw light on the 
figure, which should be dressed in black, and focus the 
dark outline shown on the sheet. A brief exposure must 
be EiTen, as it is necessary to expose lor the sheet only ; 
backed plates must be used to prevent halation, that is, 
a, spreading of light around the edges of the shaidow due 
to the light reflected from the back of the dry plate. 
Kagnesium light is particularly suitable for this work. 
When the feet are to be Included, the figure must be 
supported upon plate glass covered with thin muslin. 

Working Circular Mouldlntfs.— Fig. 1 shows a piece 
of circular moulding worked on the fiat surface. First 
cut out the rectuired shape or plan ; get the piece equBl 
in thickness and parallel in width. Sink squares as 
shown by dotted lines, taking out No. 1 square first, 
and so on ; then, with a router, as shown in Figs. 2 and 
3, work the mouldings from the outer edge. To work 
the rebate at S (Fig. 1), place the piece in the bench 
chops C (Fig. 2) and work in the same manner as shown 



skins are spread over an oval-shaped wooden bench, and 
the hair is scraped off with a tool resembling a car- 
penter's draw-knife. A similar bench Is used in fieshing 
—the next operation— in which all particles of flesh are 
cut off , the skin is given an even thickness, and the ragged 
ends are trimmed. After being washed in the revolving 
drum for thirty minutes, they a;re again fleshed to 
remove the grease, paddled in warm water, spread out 
on benches, and slated to remove surplus dirt. After 
again being paddled, the skins are drenched in a tub of 
bran and water, being paddled in the drench for twelve 
hours; this removes the last traces of lime and opens 
the pores preparatory to tanning. The latter operation 
is performed in a revolving drum, the tanning liquor 
being a mixture of alum, salt, flour, yolks of eggs, and 
water. The drum makes eighty revolutions per minute, 
and at the end of twelve hours the skins are removed 
and hung up for twenty-four hours in the drying- 
room, heated to a temperature of llO' P. The dry skins 
are damped with water and softened in a mill, con- 
sisting of two perpendicular swinging planks, having 
heavy wooden blocks at their lower ends ; in front of 




Fia2 



Working Circular Mouldings. 



tor the small member on the inner edge. Fig. 3 shows 
how the moulding may be worked on the edge of a shelf 
bracket. The router can be bought at a toolshop, or 
made with a piece of hardwood and a piece of iVih- 
thick steel. E (Fig. 2) and A (Fig. 3) show the cutter. 
The fence C (Pig. 3) may be either of brass or iron slotted 
BO as to.be adjusted. 

Preparation of Skins for Glove Making.—" Eid " 

gloves are made chiefly from lamb and kid skins, 
wliick have to pass through many processes, such as 
washing, hairing, paddling, tanning, staking, colouring, 
and polishing. First the skins, each about lit. long and 
3 ft. wide, are soaked for one or two days in cold water 
contained in wooden vats : the soaking tubs each con- 
tain about 600 skins. The latter pass to a circular 
drum having a horizontal axle, a diameter of about 
8 ft., a width of about 4ft., aad making about one revo- 
lution per second. Wooden pins projecting into the 
interior of the drum keep the skins in motion, so that a 
continuous stream of water thoroughly saturates the 
skins and frees them from dirt. At the end of flfteen 
minutes the skins are removed to the lime pits, which 
may be about 8 ft. long, 5 ft. wide, and 8 ft. deep, and 
capable of holding many hundreds of skins. The lime 
and water loosen the hairs, and at the end of a fortnight 
the skins are taken out with long-handled tongs, and 
the excess of lime is removed by placing them in cold 
water and running them backwards and forwards over a 
paddle wheel, 3 ft. in diameter, 6 ft. long, and making 
forty revolutions per minute. After this paddling, the 



these blocks the skins are placed and squeezed and 
pressed together until soft. The next operation is 
staking, performed by drawing the skins over a knife- 
edge. After a little time in the drying-room, the skins 
are again staked, this staking tending to soften the 
skins and to remove the dried flour left from the tanning. 
After ripening for a few months, the skins may be dyed, 
being first washed in a drum or cold water for twenty 
minutes and then placed for twenty-four hours in a 
revolving bath of egg-yolk, which softens the skins and 
makes them pliable. In colouring, the skins are slicked 
out smooth on a lead-covered table and washed with 
potassium bichromate and soda. The dye is then poured 
on and rubbed in with a brush. Iron sulphate is used 
for black, zinc sulphate for drab, and sulphate of alum 
for tan. After dyeing and staking, the skins are finished 
by polishing on a flannel-covered wheel. The tanned 
skins are made up into gloves as described on p. 286. 

Follsblng Paste for Brown Boot8.-A good polishing 
paste for brown boots can be made with 20 fiuid oz. or 
good malt vinegar, 10 fluid oz. of filtered water, 2 oz. of 
good glue, 1 dr. of soft soap, and 1 dr. of isinglass. 
Colour with annatto or turmeric to the shade required. 
First mix the water and vinegar, then dissolve the glue 
in the fluid by gently heating it ; add colouring and 
other ingredients, and boil from ten to fifteen minutes. 
When the mixture has been strained thoroughly, it is 
stored in jars until required for use. To use this com- 
position, lay it on with a clean sponge, and rolish with 
a soft rag or flannel. 



Cyclopaedia of Mechanics. 



79 



Tools for Engraving Letters.— Generally speaking, 
the shank or some other portion ot a letter is engraTed 
with a flat tool and finished with a lozenge graTer 
whetted at three angles. Block lettering Is wholly cut 
with a flat tool. Old English is cut with two flat 
tools of different widths, and finished with an angle 

firaver, as above. This is the reason that the work 
ooks regular and of ecjual size throughout, and is kept 
straight by worldng between parallel lines. To make a 
fiat tool for lettering, whet each side of the belly or 
underside of a lozenge graver at an acute angle, the 
sharper the better, and then rub away the angle thus 
formed until a flat is formed of a width suitable for the 
lettei-s to be cut; then sharpen as from the back as 
usual. A very_ moderate set-off or bevel is required for 
flat work, as if the bevel Is too great it will cause the 
tool to slip over the boundary lines, and consectuently 
spoil the work. Before attempting engraving on articles 
of value considerable practice should be had on a plate 
of German silver or sheet brass. For drawing outUnes, 
the onl.v instrument used is the steel tracing point or 
etching needle. 

Construction of Camera Shutter. — A camera 
abutter similar in working to the unioum is made 
as follows. Construct a grooved framework A con- 
fiistlng of a board B with an opening for flange and 

frooved rails A'. Cut two blades in ebonite, C and D. 
'he lever E, with slots F and G, is made in thin 
metal. Fasten to A' a cylinder made from a piece of 
hrass tube H, having a well-fitting piston-rod I. (A 




Construction of Camera Shutter. 



simple substitute may be made easily by winding some 
paper tightly around a piece ot knitting needle.) Two 
small rivets, fastened to the blades C and S, pass 
through the slots P and G, so that when the piston-rod 
that is attached to E is forced upwards C is raised and D 
depressed, thus opening the lens. The return ot the rod is 
caused by the suction due to the release ot the press bal}. 

Folisblng Painted Furniture.— Before painted furni- 
ture can be French polished, the paint must be removed ; 
do this as explained on p. 237. Should the furniture 
have been finished out with enamel paint or varnish 
with a spirit basis instead of paint, strong soda water, 
or a solution of hot borax and rock ammonia, should be 
used; or, If the lime is objected to, try the following, 
ilb. of American potash, ^Ib. of soft soap, ilb. of rock 
ammonia, lib. of washing soda, and 1 gal. of water. The 
outer coverings of the upholstering should have been 
removed before commencing, and they should not be 
replaced till the polishing is completed. K the furniture 
Is of mahoganjr, it should now be a dark colour, which 
only needs wiping over with red oU, made as on p. 41, 
and a trace of red in the polish to ensure a rich dark 
mahogany or Chippendale colour. A red colour Is im- 
parted to the polish by adding one pennyworth of 
Bismarck brown to each pint. In French polishing, apad 
of wadding enclosed in fine rag is used. Saturate the 
wadding, cover it with the rag, and draw it up tightly 
till it presents a face tree from creases. The pad should 
then be applied with continuous, uniform, circular 
strokes with slight pressure at first, recharging the pad 
with fresh polish at frequent intervals, taking care that 
every portion of the wood receives an equal but not 
excessive body of polish. A few spots of linseed oil 
should be occasionally applied to the face of the pad to 
prevent it sticking. If the surface of the furniture is 
uneven, it is impossible for an inexperienced worker to 
ttnish it out perfectly bright with polish only. When 



the furniture appears uniform in colour, and the grain 
is filled up, it should be finished by the application 
of at least two coats ot best quality brown hard spirit 
varnish. 

Pattern for Compassed Bed of Under-carrlage.— 

Below is described one way ot marking out a pattern 
for the compassed bed of an under-carriage. As an 
example. Fig. 1, which represents an ordinary com- 
passed bottom bed of a brougham under-carriage, is 
given. To set it out, draw the straight line A (Fig. 1) ; 
square off a line B, and from C mark oft the compass 4J in. 
to D, which is the centre of the bed. From B, mark off the 
width ot the bed back and front, as E P. At G and G, which 
ax-e the spring bearings, on each side of the centre line 
mark off distances equal to the width of the bed ; this is 
governed by the wheel-iron head. Mark off the size of 
the wheel plate, as at HH, cutting these points by half 
the width ot the compass of the bed ; then, using I on 
the square line as centre, strike a true line to the points 
D and H H. With the same radius, continue the sweep to- 
wards the end until it meets the square line/whioh should 
be about lin. inside the spring bearing G. With the com- 
passes of the same radius, describe the inner line of the 
pattern. Fig'. 2 shows the elevation of the beds when 
together, and the method of sweeping them out. The 
parts K represent the top and bottom bed plates, L the 




























































. 






















' 






















^ 


s 


■^ 








■ 




^ 


^ 


^ 


" ' 


1 


~^ 






















-^ 








^ 
























L- 








_ 












^ 





















FiG. 3 

Setting Out Pattern for Compassed Bed of Under- 
carriage. 

wheel plate, and M the transom plate ; the beds are left 
straight in the centre until the top and bottom plates 
are fitted, these being screwed on temporarily. The beds 
must be swept out as shown, care being taken to leave 
intact the bearings for the wheel plate and transom plate. 
In testing a carriage for truth, tne tools used generally 
are a straightedge, square board, and wax line. If these 
do not give a sufficiently exact result, draw a diagram as 
Fig. 3, setting the squares off perfectly true, when any 
error can be quickly seen. 

Jointing Electric Wires.— In jointing up seven-strand 
electric cables, the insulating covering is removed for 
several inches from each of the two ends to be joined, 
and the copper surfaces are scraped absolutely clean. 
They should be touched as little as possible by the hands 
to prevent any moisture reaching them. Tinned wire 
is preferable. Care must be taken that nicks are not 
made in the strands while the insulator is being removed, 
since such nicks decrease the sectional area ot the wire 
to a considerable extent. The wires are then taken and 
opened out, the two sets being placed together and inter- 
linked^ the central strand of a seven-strand cable being 
cut off short to allow this to be done. The ends are then 
well wrapped round each other, and trimmed over fairly 
smooth with pliers. Using resin as a flux, and taking 
care throughout the whole operation that everything is 
clean, the whole is then well soldered. The insulation 
on the cable will determine whether strips of pure rubber 
or ot gutta-percha should be then wound round the joint. 
The latter should be warmed by a spirit-lamp and well 
kneaded by thumb and fingers. After several layers ot 
this strip nave been applied, the whole is wound round 
with specially prepared tape. 



80 



Cyclopsedia of Mechanics. 



Bints on Choosing a DwelUng-house.— In ascertain- 
ing whether a house is a desirable dwelling place, first 
examine the walls of the house, and if settlements or 
cracks are discernible, it Is more than likely that the 
foundations are faulty; these should be bared and 
examined. Renewing or underpinning a foundation is a 
•very expensiTe operation. When any serious settlement 
takes place, stone heads ol windows show defects as soon 
as any part of the building. If the external walls of the 
house are buUt of rubble stone or brickwork, see that 
the mortar Is of good quality; a simple test is to rub it 
between the finger and thumb, when, if it crumbles 
into duet, the work will require to be repointed in a short 
time to preyent moisture penetrating. If the house is 
coyered with slates, see that zinc soakers are placed 
against the party walls. If it is covered with tiles, see 
that cement fillets ioistead of mortar fillets are used. In 
the selection of a cottage the sanitary arrangements are 
the object of most importance. It is essential, before 
purchasing, to have the drains tested by an expert. 
Never have a dustbin built again st the wall of the house i 
the contents of the dustbin will saturate the wall and 
contaminate the air of the interior. The damp course 
should be in accordance with the reciulrements expressed 
on p. 259, and must not be made of tarred felt material. 
Find out whether a proper circulation of air exists 
under the ground-floor joists, to prevent dry rot. It 
there is a drinking-water cistern, see that it does not 
directly supply a water-closet, and that the overflow 
from the cistern does not directly connect with the 
drain. The soil pipe should never be placed inside the 
house, because if it is defective in its original con- 
struction, or if it be subsequently damaged, a serious 
leakage of foul air takes place. The water-closet should 
have direct light and ventilation. The long hopper pan 
should be objected to, because it always becomes filthy. 
The sink should be in a well-lighted position and always 
against an external wall. See that none of the rain- 
water pipes have any connection with the soil pipes. As 
to the interior, see that the doors fit and are out of 
winding ; , observe the framing and see whether the 
shoulders are off— that would oe an indication of un- 
seasoned wood having been used. Look to the hinges ; 
there may be only a screw or two in each hinge. Try 
the locks and see that the furniture is fixed on securely. 
Examine the windows to see whether the sashes are too 
loose i if so, have the rattling remedied. 

Repairing Worn Watch Pivot Holes.— It la not 

necessary to plug and re-driU watch pivot holes when 
they are worn. Pui-chase some watch bouchons. These 
are brass pins, turned true and drilled accurately to 
centre. Select one that will nearly go on the pivot. 
Put it in a pin vice, and very slightly file it tapered. 
Then open out the pivot hole with a broach until the 
bouchon can be hammered in tight and broken off. File 
it level with the plate, and smooth off by stoning. Then 
open it out to fit the pivot. This method leaves the 
depth unaltered. 

Waterproofing Fabrics. — Woven fabrics may be 
rendered waterproof in a variety of ways, one of the 
commonest methods being to apply a coating of rubber 
solution and then to vulcanise the film of rub ber remain- 
ing after the evaporation of the solvent. By the water- 
proofing method of Hime & Node, zinc is added to a 
solution of cellulose in an ammoniacal copper solution ; 
copper is precipitated, and the fabric to be proofed 
is immersed in the remaining colourless viscid solution 
of ammonium, zincate, and cellulose. The impregnated 
fabric is pressed, dried, and wet-calendered, that is, 
passed between rollers. By another method, a fabric 
having a close texture is treated with sulphuric acid 
(115° Tw.) , the fibres being partly parehmentised thereby, 
and the interstices closed without the texture of the 
cloth being in any way injured. The excess of acid is 
washed out, with or without previous treatment with 
alkali, and the fabric is passed between calendering 
rolls, which complete the closing of the interstices. 
Holfert's process is to pass the fabric through a bath of 
gelatine and then expose it to the action of gaseous 
formaldehyde, the gelatine becoming insoluble. Another 
method of treatment is to apply to the fabrics boiled 
linseed oil, paints, varnishes, asphaltum, etc., as in the 
production of oilskin, tarpaulin, etc. (see p. 69). But 
one of the best of the waterproofing processes is ex- 
plained below, in which the fabric Is treated with an 
alumina ^oap. The word "soap" refers generally to 
a material used in removing dirt, and this it does by 
attacking grease and by removing the harshness or 
"hardness of the water in use. But there are soaps 
which are insoluble in or quite incompatible with water, 
and these have their use in rendering fabrics water- 
proof. The ordinary soap of commerce is in one of two 
classes— " hard " or "sott" — and is formed by boiling 
fats with alkalis. With soda as the alkaU a hard soap 
results, with potash a soft soap, these products being 
the alkaline salts of certain fatty acids— oleic, palmitic, 



stearic, etc.— derived from the fats used. When a soin. 
tion of the salt of any other metal is added to a solu- 
' tion of either of the above soaps, a precipitate of an 
insoluble soap of that metal is formed, because all but 
the alkaline soaps are insoluble in water. In this^ 
manner it is possible to produce soaps of lead, copper, 
iron, aluminium, etc. Alumina soap, so largely used in 
waterproofing, is formed from alum and soap in the- 
manner above described. In waterproofing fabrics with 
an alumina soap, one of two different methods may be 
employed. For the first method two solutions are 
required. (1) lib. of alum in Igal. of boiling water; 
(2) lib. of ordinary soap in 1 gal. of boiling water. Keep 
these solutions In separate tubs or troughs. The best 
soaps to use are palm-oil or white -curd soap, but 
common yeUow soap answers very well. The soap must 
be dissolved entirely or the coating wUl be patchy. 
When the solutions have cooled slightly, but while 
they are still warm, the cloth to be waterproofed should 
be immersed in the soap bath for about fifteen minutes^ 
so that the soap sinks into the fibre. The cloth 
previously should have been soaked in water andi 
wi'ung out. After wringing out the excess of soap- 
solution, immediately plunge the cloth into the alum 
bath, in which it may remain for an equal period, and, 
being removed, excess of alum solution may be wrung 
out also. It a thick coating of the alumina soap is 
required, the cloth may be put through this treatment 
two or three times, and, after steeping in clean water, 
it may be hung out to dry. The cloth on drying will 
be rather stiff and white, and somewhat rough, but 
will be quite waterproof ; if the roughness is objected 
to, pass over the surface a hot iron, or calender the 
cloth between rollers. Any kind of cloth may be treated 
by this method, but the most suitable kinds are those 
that are closely woven, no matter how coarse the fibre is. 
Fabrics waterproofed in this way are but little altered ; 
their feel is, however, somewhat harsh, and water 
poured over them will run off without wetting any 
part, the alumina soap having filled up all the inter- 
stices, and formed over the fibres a protective coat, 
which prevents the water touching the cloth. The 
second method of applying the alumina soap is in the 
form of a solution in petroleum ether. The alumina 
soap is formed by mixing together the boiling alum and 
soap solutions as previously prepared; for complete 
precipitation 2i lb. of soap will be required to every lib. 
of alum. The alumina soap separates out as a large 
cake, which should be collected on a piece of cloth, and 
the water sc[ueezed out. The cake may be broken up 
into small pieces, thoroughly dried at a low temperature, 
put into a dry, wide-mouthed bottle, and covered with 
petroleum spirit (benzoline) ; paralBn oil is unsuitable, 
because it forms an unmanageable stringy mass. As the 
soap absorbs the benzoline it swells and should be stirred 
from time to time so that it is mixed thoi'oughly. The 
paste thus formed may be diluted as required with 
benzoline, but care should be taken not to add too much 
of it at any one time, because on standing the mass 
becomes unaccountably fluid, and possibly too thin ; it 
this should occur, a little of the alumina soap is 
added. The waterproofing solution made in this manner 
may be laid on the cloth with a brush or, better, by 
passing the material through rollers fed with the solu- 
tion. After treatment, the cloth should ibe hung out for 
a short time in the open air to allow the benzoline to 
evaporate. If a thicker dressing is required, the cloth 
may be coated two or three times ; for ordinary pur- 
poses, however, once is quite enough. The alumina soap 
may be coloured reddish-brown by the addition of a 
little perohloride of iron in place of some of the alum, 
and green by the addition of sulphate of copper (blue 
vitriol). It is also possible to obtain other colours by 
employing solutions of other metals, but these are more 
or less expensive. The common colours, yellow and 
black, may be imparted by stirring in yellow i chre or 
lampblack with the soap solution in the first method, or 
by kneading it with the alumina soap in the second. 

Carrying Camera on Cycle.- The best way of carry- 
ing a camera on a ojrcle is a much-debated question. 
The slides may be carried knapsack fashion on the back 
of the rider, the stand across the top bar of the frame, 
and the camera slung in a case over the back wheel. On 
a lon^ journey, however, it is uncomfortable to carry 
anything on the back. If the apparatus is carried on 
the handle-bar the vibration is very great, and shutters, 
etc., soon get out of order ; dust also readily accumu- 
lates. The dust trouble, however, may be easily overcome 
by carrying the camera and slides in dust-proof or close- 
fitting oases, and where the springs in the dark slides 
do not keep the plates tightly in position, a piece or 
rubber tubing put between one of the plates and the 
backing card will often overcome any vibration. But 
anything bulky on the handle-bar is liable to affect the 
steering, and increases the danger of side slip, while 
anything carried within the frame of the machine may 
make the pedalling very uncomfortable. 



Cyclopasdia of Mechanics. 



81 



Killing Butterflies.— To kill, plnoh them under the 
wlngB between the finger and thumb, or, for a collec- 
tion, procure a " killing bottle," which may he bought 
from most naturalists, or may he home-made. Get a 
wide-mouthed bottle, provided with a good cork or 

§lass stopper, and into this put an ounce (for a 4-oz. 
ottle) of cyanide of potassium in lumps. Then mix up 
some plaster-of -Paris, and pour this upon the cyanide, io 
as to cover it completely. Give the bottle a shake as the 
plaster is setting, so that it forms an even surface, and, 
when quite set, cover the plaster with a piece of blotting- 
paper to absorb the moisture and to keep the insect 
from contact with the damp plaster. This blotting-paper 
should be renewed when necessary. The cyanide is a 
deadly poison, so must be used with care, and the bottle 
kept corked. Put the insect into the bottle, cork it up, 
and leave the Insect in for about ten or fifteen minutes. 
A few drops of strong spirit of ammonia poured on a 
piece of cotton-wool in a bottle will also form a killing 
bottle. Bruised laurel leaves may also be put into a 
bottle, and prussic acid will be given off, thus forming 
another killing bottle. A few drops of chloroform poured 
upon blotting-paper at the bottom of a bottle will also 
stupefy the insects to death. Nothing is required to 
preserve butterflies. 

British Association Screw-threads.— The following 
table gives particulars of the Swiss small screw gauge 
as adopted by the British Association ; — 



No. 


Diameter (ap- 
proximate) 
in Inches. 


Pitch in 


Diameter in 


Pitch i» 


Threads 


Inches. 


Millimetres. 


Millimetres. 


per IiKh. 


25 


•01 


•0028 


•25 


•072 


353 


2i 


■Oil 


■0031 


•29 


•08 


317 


23 


■013 


•0035 


•33 


•089 


285 


23 


•015 


•0039 


•37 


•098 


259 


21 


•017 


•0013 


•42 


•11 


231 


20 


•019 


•0047 


•48 


•12 


212 


19 


•021 


•0035 


•54 


•14 


181 


18 


•024 


•0039 


•62 


•15 


169 


17 


•027 


•0067 


•7 


•17 


143 


16 


•031 


•0075 


•79 


•19 


134 


15 


•0'35 


•0083 


•9 


•21 


131 


14, 


•O-'fl 


•0091 


1 


•23 


110 


13 


■on 


•0098 


1-2 


•25 


101 


12 


'031 


•Oil 


1-3 


•28 


90-7 


U 


•059 


•0122 


1-5 


•31 


81-9 


10 


•067 


•0138 


1^7 


•35 


726 


9 


•075 


•0154 


1^9 


•39 


651 


S 


•086 


•0169 


2-2 


•43 


59^1 


7 


•098 


•0189 


2-5 


•48 


52-9 


6 


•11 


•0209 


2-8 


•53 


■ 47^9 


5 


•126 


•0232 


3^2 


•59 


43 


i 


•142 


■026 


3^6 


•66 


38^5 


3 


•161 


•0287 


41 


•73 


34^8 


2 


•185 


•0319 


4-7 


•81 


31-4 


1 


•209 


•0334 


5-3 


•9 


28-2 





•236 


•0394 


6 


1 


25-4 



Double-action Harp.— The action is complicated, 
and unless it works with the greatest accuracy it is 
worse than useless. Briefly, the principle consists in 
placing beneath the wi^est-pin a small collar having 
two studs fastened on its " flat " similar to a " wing-nut, 
the whole working on a stud through the head. These 
are connected by a system of levers in head and pillar 
to the pedals, pressure upon which causes a partial 
revolution of these collars, between the studs of which 
the string passes, audis consequently tightened or raised 
in pitch, various pedals are required; for instance, 
one for P sharps, another for sharps, and so on, each 
pedal affecting only the notes of the same name through- 
out the instrument. 

Laying Bed Tar-paving. — A very duU red tint 
may he obtained by using crushed red granite 
instead of limestone. The objection is that each 
particle of granite has a smooth surface, and the tar 
does not adhere satisfactorily. The cost will be from 
Is. lOd. to 2s. 3d. per superficial yard. Another method 
is to dye the limestone with red oxide of iron ground 
very fine. The ordinary method of laying may be 
adopted, and the cost will be from Is. 6d. to 23. per 
square yard. 

Toughening Paper.— Soak ordinary unsized paper in 
sulphuric acid {2 parts of acid to 1 part of water) for a few 
minutes, then thoroughly wash it with water containing 
a little ammonia until no trace of acid remains, and let 
it dry. This is "parchment" paiier, and it is not much 
less pliable than the untreated kind. 

Straightening Warped Fretwork. — The warping 
or twisting of fretwork is ofttimes counteracted by 
the use of three-ply wood — that is, three pieces of 
▼ery thin board or veneer glued together the middle 



one being transverse to the others. 'Warping is often 
caused by excessive polish being applied to one side 
only, without a coat of varnish on the back to counter- 
act. Nothing can afterwards he done, except to take 
the brackets apart and slightly damp them with clean 
water ; screw tneni down between two stout boards till 
straight, then apply polish or varnish on both sides. 
There will still be the tendency to twist back again 
if the brackets are put in a hot place. 

Bending and Fitting Rlhs for Small Boat.— 

Use straight-grained American elm or oak, the former 
for preference. After being shaped and dressed, the ribs 
are steamed or soaked in Doiling water till pliable, and 
bent over the knee where necessary. The ribs on either 
side are notched to fit over the keelson, and butt against 
each other where they cannot be carried right across. 
The keelson must not be cut ; the ribs are usually spaced 
closer in the bow to add strength. Floor ribs extending 
on either side of the keelson and between the others are 
also notched and fitted over the keelson. A fore and aft 
stringer on either side is then screwed to both sets of 
ribs, which bind the whole together. 

Cementing Felt to Iron Rollers.— To make a cement, 
cover glue with moderately strong acetic acid instead of 
with water, and treat it as for ordinary glue. Another 
cement is made by dissolving 2 parts of shellac and 1 part 
of Venice turpentine in 7 parts of methylated spirit. For 
a firm hold the cylinders should not be quite smooth. 

Electric Current Carrying Capacities of Copper 
Wires. — The following table is based on a current 
density of 1,000 amperes per square inch ; the loss will 
then be 2 volts for 80yd. :— 



No. S.W.G. 


DiaTMter in 
Inches. 


Area in Sqimre 
Inches. 


Current in 
Amp^es. 


22 


•028 


•0006 


•6 


20 


•036 


•ooio 


1 


19 


•040 


•0012 


1^2 


18 


•018 


•0018 


1^8 


17 


•056 


•0024 


2-4 


16 


•064 


•0032 


3^2 


15 


•072 


•0040 


4 


14 


•080 


•0050 


5 


13 


•092 


•0066 


6^6 


12 


•104 


•0083 


8^5 


11 


•116 


•0105 


10^5 


10 


•128 


•0128 


12^8 



It is unnecessary to add stranded cables to the above 
table, as their working currents may be calculated 
direct from it. For instance, 7/16 S.W.G., consisting of 
seven strands each TSo. 16 S.W.G. in size, will carry 7 x 32 
= 22^5 amperes (say). Similarly, 19/14 S.W.G. will carry 
19 X 5 = 95 amperes. For currents at other current 
densities, multiply the current given in the table above 
bjr the density required in amperes per square inch 
and divide by 1,000. Thus, with a current density of 
600 amperes per square inch, with a drop of 2 volts per 
160 yd. (see reply 16210 on p. 333) , No. 22 S.W.G. would carry 

■6 X ^35_ = '3 ampere. It may be well to add that the size 

of any single wire should not he reduced below No. 18 
S.W.G. ; smaller sizes are mentioned in the above table 
so that the current capacities of stranded wires may 
be calculated. Also, sometimes the simplest way to 
find the drop in volts is to multiply the resistance in 
ohms of the given length of cable by the current in 
amperes. 

White Spots on Polished Furniture.- These may be 
caused by water spotting, damp, or the use of plaster-of- 
Paris as a grain filler. Try rubbing the surface with a 
mixture of equal parts of linseed oU, turpentine, and 
vinegar ; then clean oft any greasiness that may remain 
by means of a swab of clean soft rag made f aix-ly damp- 
not wet— with methylated spirit. Apply this lightly at 
first, then, as it becomes drier, press a little harder and 
finish in the direction of the grain. 

Making Tongues on Spokes of Cart Wheels.— 
Take off the tips of the spokes to about the size of 
tongue required with a tool somewhat like a large coun- 
tersink inverted, with cutters inside, then with the hollow 
bit cut down to ttopth ; this outs the shoulder at the same 
time as it makes the round tongue. To do it by another 
method, mark in the trout of the tongue parallel with 
the set-stick fixed to the front of the stock, by which the 
spokes were guided when driven in ,: then mark off the 
diameter, saw in to these marks to ' ck and front, split 
off, and with the draw-knife pull It out short at the 
sides and trim up round, using a fitter to guide the size. 
A tongue made this way is much stronger than when 
the shoulder is cut in square all round, as the grain at 
the side of the spoke is not cut so short. 



82 



Cyclopaedia of Mechanics. 



Preparation of Pitch Pine for .Varnishing.— 

Pitch-pine furnitui'e is generally flnished by the 
application of several coats of good auality spirit 
vai-nish. Interior fittings likely to oe euDject to hard 
wear ai'e hest flnished with a good oil Tarnish, such as 
Chnrch oak. Pitch-pine goods are sometimes first coated 
with size, with a Tiew to prevent suction. Many have a 
preferencetor first coating with spirit varnish, as it gives 
the articles a good colour, and any good quality oU. 
varnish will dry thereon. If a first coat of varnish is 
not sutflciently hard to allow fiatting with pumice in 
three days' time, the drying qualities are poor, or it may 
have been applied too thickly or by a dirty brush. Drying 
may sometimes be hastened by sponging down with cold 
clean water. Another plan is to coat with naphtha or 
spirit varnish ; the result can also be gained by coating 
again with a thin oU varnish, the dr.ving qualities or 
which have been hastened by the addition of japanner's 
gold size. 

Cutting out Umbrella Covers.— For umbrella covers, 
first malce the pattern by which to cut out the 
sections or gores. This may be of strong paper, but for 
permanent use sheet zinc is best. First cut a square of 
paper, each edge of which is exactly the same length as 
the frame on which the cover is to be placed— that Is, a 
25-in. frame would take a square of paper with edges 
25 in. long. Cut tills across from one corner to the oppo- 
site corner to produce a piece shaped Uke A B in the 




Pattern for Umbrella Covers. 



illustration. Measure from A towards C the same distance 
as from A to B (in this case 25 in.), and then cut along the 
line D B. The part A D B now forms the complete pattern. 
By measuring down the centre as shown by dotted line, 
the width of cloth necessary to cut the cover will be dis- 
covered. For 25-in. covers cloth 22 in. wide is required. 
Always place the edges B D towards the selvedge edges 
of the cloth being cut, and allow a margin for hemming 
and sewing together. Sew the top of the cover with 
strong thread after machining. 

Flow of Water over a Weir.— The following is a rule 
for finding the exact discharge of water in cubic feet, 
or gallons per second, passing over level weii-s. The 
depth of the water on the weir x width x velocity, 
all in feet, will give cubic feet, and this x 6i will 
give the discharge in gallons. To find the exact 
quantity of water that is flowing over a weir would be 
a very difficult matter unless proper provisions were 
made for gauging the depth of the water and its velocity. 
For rough approximation the depth would be the differ- 
ence in level between the weir and surface of still water 
above it, but with an allowance for curvature of the 
surface on the weir, which varies considerably. For the 
velocity it would be necessary to time the movement 
of a floating object, and from this make a deduction, as 
the surface travels at a higher speed than the bottom. 

Hints on the Manufacture of a Speculum,— 

In the manufacture of specula, plate glass is used, 
provided the size of the mirror is not such that the disc 
has to be specially cast. The thickness is in proportion 
to the diameter, the general ratio being as 8 to 1— that is 
to say^ the diameter of the speculum should be eight 
times Its thickness. A safer ratio is 6 to 1— at any rate 
for large mirrors, where the question of flexure is an 
Important consideration. Supposing the diameter of 
the speculum to be 10 in., its thickness would be l|in.— 
certainly not less than It in. Before deciding the 
curve, the focal lenifth of the speculum must be de- 
termined, as this, of course, in turn determines the 



length of the telescope. If the latter must be short, the 
former must be short also, and the cui-ve of the mirror 
must be correspondingly deep. This will rendfer the 
figuring much more difficult to work than when the 
speculum has a long focus. The general practice is to 
make the focal length twelve times the diameter of the 
mirror, which, in the case of a 10-ln., will be 10 ft. The 
curve of a speculum, though first ground spherical, is 
not left so, but is deepened to a j)arabolic form, as it is 
found that a spherical surface is unfitted for astro- 
nomical work. Parallel rays, when received on such a 
surface, result in an indistinct image at the eyepiece. 
Practical experience shows that the cui've should be 
such that parallel rays received on it will come to a 
focus midway between the mirror and its centre of 
curvature. Therefore, in a 10-in. speculum the curve 
must be part of the circumference of a circle having 
a radius of 20 ft. 

Making Zinc Stencil Plates.— Zinc stencil plates foi 
marking boxes and sacks maybe cut by hand with the aio 
of a mallet, a sharp chisel, a pair of bent-nosed snips, and 
a plate of thick sheet zinc. Taking the letter 0, shown by 
the accompanying diagram, commence by drawing the 




Ilalcing Zinc StencU Plates. 



letter ; then , assuming that the inside part of the figure 
is to be held by the straps A B, A B, take the chisel, and, 
laying the stencil plate upon the sheet zinc plate, cut it 
through along the lines A a, B b, then, with a circular 
hollow punch, punch out the holes X, X, X, X. Insert 
the nose of the open snips through the holes alternately, 
and cut through the zinc to the corners A a, B b on both 
sides of the figure ; then, from the open spaces formed, 
cut round with the snips upon the lines drawn, smooth 
the burr down upon an anvil with a few blows from 
a smooth mallet, and trim the cut edges with a smooth 
file to finish the plate. Letters formed by straight lines, 
as E or P, can be out by the use of the chisel only. 

Etching on Steel.— To write names, etc., on steel 
cover the surface to be marked with a thin layer of 
asphaltum varnish, making a little bank at the edges. 
On the varnish write the names, etc., with a steel 
scriber, and, in the small basin formed by the asphalt 
banks, pour a weak solution of nitric acid. TVlien this 
has eaten in to the required depth, wash with hot water, 
removing the varnish with hot turpentine. Instead or 
asphalt varnish, soft beeswax is often used, and an 
etching fiuid may be made from iodine I oz., iron filings 
4 dram, and water about i oz. A solution of iodine, 
potassium iodide, and water is sometimes used ; also a 
solution of I part of nitric acid (by measure), I of hydro- 
chloric acid, and 10 of watet. 

Dyeing Curtains and Tablecloths Turkey Bed.— 

The red ^ye fastest to light, washing, etc., is alizarin or 
Turkey red. For wool, mordant with a bath of sulphate 
of alumina and cream of tartar, and dye in a bath of 
alizarin paste and acetate of lime. For 100 lb. of wool 
use 10 lb. of sulphate of alumina, B lb. of cream of tartar, 
10 lb. of alizarin paste, and 5 lb. of acetate of lime. The 
dyeing of cotton is a more complicated process. 



Cyclopaedia of Mechanics. 



83 



Faint Blistering on Woodwork.— Blisters in almost 
all cases are due to the escape of moisture that is 
present in all wood, new or old. Nevr wood is, of course, 
more liable than old to glye off moisture, and the paint 
to become more blistered ; but old wood will show the 
■ same effect if exposed to the heat of the sun. It may be 
that exposure to the sun Is the cause of the paint blister- 
ing on this particular door, and in that case the only- 
remedy is to hang oyer it a kind_of sun-blind, made of 
plain or striped canVSis, during the summer months. 
This is a very general practice in the London suburbs, 
and is found to be the best protective. If the door is to 
be repainted, then see that the work is done in dry 
weather and with dry brushes. The old paint wilj have 
to be burnt off, and more turps and less oil may be 
used with advantage in mixing the new paint, as a more 
porous film of paint will in this way be obtained. 

Fixing Mooring Bollards.— For mooring steamers of 
about 900 tons, the concrete block for the mooring 
posts or bollards should be not less than 7 ft. 6 in. 
square and 8 ft. deep, with a block of Bramley Fall 
stone 5ft. square and 1ft. Bin. thick on top. The 
part of the bollard above the ground line is usually 
a separate casting, securely bolted to the founda- 
tion column, which is bedded in the concrete, with a 
flange at the bottom bolted to two 12-in. by 12-in. baulks 
of creosoted memel. The shape of the upper casting 
varies from a post with rounded head and hollowed side, 
or a capstan-head shape, to a tall or short hook shape. 
The thickness of metal is about IJ In., tapering to 1 in. at 
the bottom of the concrete. The diameter where the 
rope goes is about 18in., and the bottom end 15 in. The 
engineer of the dock usually gives the design both for 
the bollard and the foundation, as every part must be 
calculated to do its duty efficiently. 

Adding an Electric Alarm to a Clock,— To fix 
an electric bell to a Vienna regulator clock, arrange 
the electric circuit so that the battery is in a con- 
venient position, and the beU in the bedroom ; include 
the clock in the circuit. One wire should be carried 
through the case and soldered or screwed to any part 
of the brass movement, preferably the front plate. 
The other wire should be carried to the edge of the dial, 
and should lie flat upon it pointing towards the centre, 
the end being brightened and hammered flat so as not to 
stand up much from the dial surface. A piece of paper 
gummed on the dial beneath it yrill serve to insulate it. 
The connection is made by the hour hand having a thin 
flexible piece of brass soldered to the end of it to make 
contact with the copper wire at the dial edge as it passes 
over it. This extension may be painted white, so as not 
to confuse the eye. This arrangement will make contact 
every twelve hours, but may be switched off during the 
day. 

Reading a Gas Station meter. — The gas made 
on a gasworks is always measured by the station 
meter, and in modern establishments corrections are 
made for temperature and pressure, in order that 
the gas may be measured under standard conditions, 
since, as the height of the barometer, and more 
especially the temperature of the atmosphere, varies at 
different seasons of the year, the measurement of the 
gas w affected in accordance with the atmospheric con- 
ditions prevailing j hence, in practice, the volume of gas 
passing through the station meter is always reduced to 
the standard conditions of 60° F. an* a barometrical 
pressure of 30 in. of mercury. Thecalculations are based 
upon the following physical laws. By the law of Boyle or 
Marlotte, the volume of a given mass of any gas, assum- 
ing that the tempern.ture is constant, varies inversely as 
the pressure to which it is subjected j or, in simple 
language, doubling the pressure reduces the volume to 
one-half, while, conversely, reducing the pressure one-half 
doubles the volume, and so on in a similar ratio. Now, 
supposing a station meter registered 10,000 cub. ft. oi gas 
under a barometrical pressure of SO'Sin., and we wished 
to reduce the volume to the standard pressure of 30in., 
since the pressure under which the gas is measured is 
greater than the standard pressure (30 in.), it is plain 
that under the last-mentioned pressure the volume 
would be greater ; consequently, we say. 

As 30 : 30-5 : : 10000 : 10166 cub. ft. 
Or, supposing that we measure the same volume of gas 
under a pressure of 29'5in., and we wished to know the 
volume at the standard pressure j in tills case, the gas is 
measui'ed under a lesser pressure than the standard, 
consequently, when reduced to the latter pressure, the 
volume would be reduced ; so in this case we say. 

As 30 : 29-5 : : lOUOO : 9833 cub. ft. 
It will be noticed that in each case the standard pressure 
(30 in.) occupies the first term in the statement. With 
regard to temperature, as is well known, gases expand 
with heat and contract with cold, and the amount of this 
is expressed as follows. The volume of a gas expands or 
contracts by tH part of its volume at 32° F. for every 
increase or decrease of 1° P. Now supposing we measure 



10,000 cub. ft. of gas at a temperature of 80° P., and we 
wish to correct it to the standard temperature of 60° F. 
(the pressure remaining constant) , 492 volumes at 32° F. 
become 492 + (60 - 32) = 520 volumes at 60° P., and 
492 -I- (80 - 32) = 540 volumes at 80° P. The volume, 
therefore, of any gas at 80° P. would bear the same ratio 
to the volume which it would occupy at 60°iF., as 540 does 
to 520 i consequently, 

As540 : 520 :: 10000 : 9629 cub. 'ft. 
If the gas, instead of being measured at 80° F., had been 
measured at 40° P., then, as before, 492 volumes at 32° P. 
would become 520 volumes at 60° P., and 429 volumes at 32° 
P. would become 492 + (40 - 32) = 500 volumes at 40° 
F. Then the ratio of the volume at 60° F. would be 
obtained as follows— 

As 500 : 520 :: 10000 : 10400 cub. ft. 
It will be noticed that 520 always occupies the second 
term in the proportion. In practice, the volume of a gas 
is always corrected for temperatui-e and pressure at one 
operation by combining the two corrections and making 
a compound proportion sum of it, and as two of the 
terms always , occupy the same position, by cancelling 
we obtain this expression- 

■ "^.L" .''.'' ^ = corrected volume. 
400 -t- 6 
p being the pressure under which the gas is measured, 
V the volume, and t the temperature under which the 
gas is measured. In gasworks, however, these correc- 
tions are usually performed by means of a series of 
tables drawn up by the Metropolitan Gas Referees, based 
on the principles already explained, but also taking into 
account the tension of aqueous vapour, the formula from 
which their numbers are obtained being — 
17-64 (6 - g) X V 
460 + t 
a representing the tension of aqueous vapour to be 
deducted from the height of the barometer according to 
the temperature under which the gas is measured, while 
17-64 only differs from the 17-333 previously given by 
deducting from 30 the tension of aqueous vapour at 60° 
P. By the aid of these numbers all that is required is to 
observe the temperature of the thermometer at the inlet 
of station meter, and the height of the barometer, then 
find the number corresponding to them, and multiply 
the volume of gas by the number, when the corrected 
volume at 60° P. and 30 in. will be obtained. 

Smoky Kitchen Chimney.— It 1^ unusual for close-fire 
kitcheners to give trouble bjr smoking, and unless 
the cause is dawn-blow (which only opcurs when 
the wind blows from certain quarters), then it 
must be concluded that the range is not properly 
fixed. Supposing the chimney is clear, it should be 
ascertained whether the brickwork of the chimney 
above the range is well clear of the fiiie outlets. There 
should be at least 12 iu. clear space between the flue 
outlets at the top of the range and any brickwork 
that may come above them. If all is right in this 
direction, then ascertain whether there are any means 
by which air can enter the chimney from the room 
without passing through the fire, which is a common 
cause of kitcheners working badly, though it may not 
always make them smoke. The range should be set 
sound and air-tight, and there must not be any other 
flues running into the range chimney, except, perhaps, 
the copper flue, which must have a damper, to be closed 
when the copper fire is not alight. There must not be 
openings of any kind by which air can pass into the 
kitchen chimney except it go through the fire. It must 
be ascertained that the soot doors are complete and in 
their places, and that there are no apertures in the 
chimney. The position of the fire in its relation to the 
room door need not be considered with these close-fire 
ranges. 

Removing Fat from Sheepskins.— Practical curriers 
immerse the skins in fermented bran and water. "Wash- 
ing the skin in a solution of potash will also remove 
surplus oil; so also will soap andT soda and water. Having 
taken away the oil, stretch the skin out to dry, and, 
whilst it is doing so, scrape it and rub it iu every direc- 
tion to prevent it drying hard. 

Brass Polishing Composition. — Crocus is very 
good for polishing any metal under the hardness of 
iron, and it may be used for finishing iron and 
steel, after the rough polishing is done. It may be 
made into hard cakes by mixing with lard, suet, or 
tallow, first melting the tallow and then stirring in 
as much crocus as the tallow will hold, and pouring 
into an open oblong box, the sides of which may be 
taken apart to release the cake. For a paste to be 
put up in tin boxes, the crocus may be mixed with 
soft soap, with a percentage of a common oil to be ascer- 
tained by experiment, the oil preventing the paste from 
becoming hard. The former composition would be use- 
ful for lathe polishers, and the latter for domestic and 
general use. 



84 



Cyclopaedia of Mechanics. 



Fbotographlng a Procession Instantaneously.— 

To take a series of photographs of a procession, the 
camera shoulcL be directed up the road so that the 
procession is shown approaching. Do not attempt to 
take the procession broadside on, as the exposure will 
need to be much more rapid owing to the moTeraent 
appearing far more noticeable. The most rapid plates, 
Oadett "Lightning" or Ilford Special Rapid, should be 
used. The light varies so that it Is practically impossible 
to say what exposure to give. Much will also depend upon 
the surroundings, direction of light, and the character 
of the procession— that is to say, whether the clothing of 
the processionists Is dark or light. Experienced photo- 
graphers usually endeavour to make a couple of trial 
exposures on the crowd a little before the event ; by 
developing the plates at once they are enabled to get an 
idea of the exposure required. For the trial exposure use 
full aperture, and let the shutter work as quickly as 
possible. Develop one plate first and make a print ; from 
the result it may be possible to suggest how the subse- 
quent prints may be improved. Two or more cameras 
clamped to the window frame should be used. They 
should be focussed before the procession arrives. 

Forging Rods for Engine.— To forge the two rods 
shown In the accompanying dimensioned sketches. 
If steel were used and a steam hammer available In an 



T^^ 



[t 



Fia 1 
C 



8 




Forging: Rods for Engine. 

engineer's shop, the webs might be drawn down from 
the larger ends. Iron of common quality should be 
welded so that the fibre in the flat ends may run length- 
ways of the ends ; or the ends would be opened out to 
form the flat. Again, Where there is uncertainty about 
exact centres, as In valve setting, welding up to length 
is often done after the fitting of the ends. For con- 
venience, the web may be drawn down from both ends, 
and welded about the middle or towards one end. The 
forked ends are, when in the dimensions given by the 
ooiTespondent, forged solid, and then slotted out. They 
might, however, be forged roughly to dimensions over 
a former block, leaving little to be tooled out. As a 
general rule, the greater the difference In the dimen- 
sions of the two enlarged ends the greater the reason- for 
drawing down from two pieces, and then welding. Up- 
setting to any considerable amount is objectionable 
both in iron and steel. If the whole of the work must be 
done on the anvil without a steam hammer, make the 
two ends as separate forgings, and weld the web to them 
with two welds (O, r) in the case of Pig. 1, and with one 
only (H) in Pig. 2, more drawing down being necessary in 
the case of Pig. 1. For the feet A, take a piece of flat bar 
and draw down the portion as far as H, fullering it on 
faces and edges alternately, and leaving the end upset 
for welding to the web. The inner face J is brought 
fairly flat by up-ending the broad face on the anvil and 
going over J with a hammer first, and Hatter afterwards. 
The blows tend to make the forging strike backward, so 
a block (Fig. 3) must be set in the shank hole of the 
anvil as a support. For the other ends B, B a bar will be 
taken a little larger than the finished section, and the 
webs will be drawn down to J? in Fig. 1, and to H in Fig. 2. 



There is very little drawing down In the latter case. AU 
the weld ends must be upset, and the joints scarfed and 
rounded (Fig. i). The lengths of the welds need not 
exceed It in. Centre pops and a fixed trammel must be 
used to check the lengths during welding. 

Damp Preventive for Brickwork and Stucco.— 
For painting brickwork and stucco exteriors to repel 
the damp, amongst many other materials the following 
have been recommended: (1) Boiled oil applied hot; 
(2) soft soap and alum, the latter applied twenty-four 
hours after the former ; (3) Ozerelmy fluid, presumably 
a silicate ; (i) boiling tar ; (5) silicate or other-good oil 
paint. For stucco work a coat of Portland cement as 
thin as cream, applied with a whitewash brush i boiled 
oil applied hot and afterwards painted regularly; 
ordinary oil paint applied regularly. 

Making Trousers Stretchers.— The simplest form 
of trousers stretcher Is that Illustrated by Pig. 1; 
It is known as the " Invisible " trousers stretcher, 
as It is used by putting it inside the trousers leg. 
It Is made of stout iron wire. The dimensions are 
as follows: A to B (Pig. 1), 30 in.; C to D, 29i in.; 
Ato G, 14} iu.; B to D, 15in.; A to E, lin.; E to r,14in. 




Trousers Stretchers, 

Of course, one Is required for each leg. The device Is 
patented. Another kind is that shown by Pig. 2, which 
18 drawn on a larger scale than Pig. 1. Pour pieces of 
wood, iln. thick and U in. wide, are required; two 16in. 
long, and two 13 in. Holes are bored near the ends, and 
the pairs are fixed together by small bolts and thumb- 
screws. The longer pair belong to the top of the 
stretcher. A metal socket is screwed on at A (Fig- 2> 
to receive the end of the bar, and there is a receptacle 
at B (Fig. 2) having a thread in It, through which the 
screw of the rod is turned. The rod, which is of metal, 
is about 33 in. in length, and has a screw for about 6 in. 
of its length from the top. Trousers should be folded by 
bringing the two front brace buttons together with the 
left hand, and then taking each bottom at 31 in. from the 
side seam, and bringing them together also ; the crease 
thus formed is the centre line of the leg. The trousersare 
thus laid in the stretcher, the bottom being fixed first, 
and the screws tightened ; then the top as far up the leg 
as it will go, and the stretching Is accomplished by 
turning the ring at the top. The articles should then 
be left for some time. 

Filling Cracks In Blackboard.— As a filling for 
cracks and holes in a wooden blackboard, if the 
crack is Jin. or more in width, a slip of wood should 
be fitted and glued in the opening and afterwardB 
planed down level to the surface of the board. But il 
the crack is less than i in. wide, it can be filled in with a 
mixture of plaster-of-Parls, glue, and a little lampblack. 
This should be allowed to dry, and then scraped and 
glasspapered flush with the surface of the board. 



Cyclopaedia of Mechanics. 



85 



Benovatlng Lacciuer of Microscope.— To clean a 
microscope that has become rusty through lying in a 
damp place, well rub the affected parts with paraffin. It 
the spots are merely superftoial the paraffin will fetch 
them off; but it the damp has penetrated deeper, the 
only remedy is to remove the entire coating of faoqiuer, 
re-polish the metal, and re-lacquer. To do this, remove 
the lenses, take the microscope to pieces, and boil the 
lacquered parts with a handful of strong soda in water. 
This will remove every trace of the old lacquer. , When 
dry, with some No. 1 blue-black emery paper grain the 
pieces as before. The old graining will give the direc- 
tion. When all the pieces, screw-heads, etc., have been 
separately grained, they must be separately heated and 
lacquered. The draw tubes, if stained, need only be 
cleaned up with paraffin ; but if it is thought desirable 
to paper them also, they miist not be lacquered, but 
should be rubbed over with vaseline instead. 

Silvering Brass and Copper.— Any article of brass 
or copper can be silvered bj^ the Frenchtsilvering 
process as follows : Dissolve a stick of nitrate of silver 
in i j)t. of water ; add common salt, which will deposit 
the silver in a white mass at the bottom. Pour oft the 
water and add fresh, stir up, allow to settle, and pour 
off again. The residue is silver chloride. To use it, 
clean the metal with fine emery-cloth, wash it in 
cold water, and rub its surface with salt brine. Then 
rub it over with a rag on which is a paste composed 
of equal quantities each of silver chloride, cream of 
tartar, and water. Continue rubbing until it is evenly 
silvered all over, then wash in jjleuty of water and dry 
with a soft clean cloth. Any silver chloride not used 
can be dried in the dark and kept in a bottle away from 
the light for future use. It is best to silver by gaslight 
or weak daylight. 

Duresco and Petrifying liquid.- The nature of 
DuresQO and petrifying liquid, ana the proper way to 
use them on damp walls has been explained as follows : — 
Duresco is a water paint consisting of pigments 
ground up in a medium containing water; petrifying 
liquid, as made by the Silicate Paint Co., is a solution 
containing certain chemicals which combine with stone, 
etc., to form a hard, impervious coating ; the same result 
Is obtained when Duresco is thinned with the petrifying 
liquid and applied to walls. For application to damp 
walls, the Duresco body colour must be thinned with 
petrifying liquid or Duresco liquid in the proportion of 
1 to i. Duresco is very often effectual on interior damp 
walls, but the benefit cannot be considered permanent, 
as continual dampness entering the walls from the out- 
side rots the plaster. Duresco is no good in cases of 
dampness arising fi-om foundations., The cause of the 
dampness must first be removed. Three coats of Duresco 
should then be applied thinned down with the petrifying 
liquid. Petrifying liquid alone will prevent moisture 
penetrating, but is not so effectual as Duresco, and Is 
only used where a painted effect is not required. Three 
coats of this should also be given. Duresco and petrify- 
ing liquid are both patents. For porous bricks, Duresco 
should be applied outside the house. 

Camera View Finder.— A view finder is an apparatus 
in which can be seen a miniature representation 
of the picture that is thrown on the ground-glass 
screen of the camera. It is fixed outside th6 
camera in such a position, that when the image is 
focussed sharply on the ground-gI6,ss screen, the 
finder shows the same image just as sharply focussed. 
When a finder is used, therefore, it is unnecessary to 
focus the picture on the screen, the finder being used 
instead, and the convenience of such a procedure is 
obvipus. A finder is absolutely necessary with a hand 
camera, and a very valuable adjunct to a stand camera. 
Care should be taken to see that the finder includes 
no more of the view than is shown on the screen of the 
camera. If the finder includes too much, reduce it to 
the proper dimensions by pasting strips of dark-coloured 
paper on the screen of the finder. 

Tuning a Piano.- A wedge, a tuning hammer, a piece 
of ivory, and a tuning-fork are necessary. About 
7s. 6d. should be paid for the hammer, for unless tbe 
temper is good the continual strain will soon cause it to 
wobble on the pins. Care should also be taken to ensure 
its adaptability for the instrument in hand ; thus, some 
instruments are fitted with square heads, others with 
oblong ones to the tuning-pegs. The wedge is used to 
stop the vibration of one string of a note whilst the 
other is tuned. Wedges are usually made of lancewood, 
rosewood, or whalebone about 8in. long, Jin. wide, and 
i^in. thick, each end being covered with varying thick- 
nesses of doeskin ; they cost about Is. each. The piece 
of ivory is generally a portion of an old key covering, 
and is used for the purpose of plucking the wires in the 
first stage. A C tuning-fork costs aboijt Is. 3d. Tuning- 
forks should never be struck on any hard substance ; 
such practices have a tendency to flatten them. Tuning 



may be said to embrace four stages— chipping up, rough 
tuning, tuning, and fine tuning! space will not permit 
of each stage being full}; dealt with. Briefly, after the 
Instrument leaves the stringer's hands it is chipped up— 
that is, the action is left out, the wires being merely 
plucked with the piece of ivory referred to ab.ove. When 
all the wires have been somewhat pulled into tune the 
action is put in and the tuning is followed through 
various stages by means of the hammer and wedge. As 
the tuning-pegs are merely held in position by being 
turned into a wood plank, care should be taken to 
prevent any unnecessary wriggling about; especially 
avoid straining the pegs upwards or downwards, instead 
of turning them. It requires a firm grip and strong wrist. 

Yellow Stain for Oak. — A suitable stain is 
gamboge, steeped in methylated spirit ; this yields a 
powerful yellow tone. It this, or turmeric, does not 
suffice, try lemon chrome mixed In 1 part French polish 
and 3 parts spirits ; or a yellow aniline dye, mixed with 
3 parts water and 1 part vinegar. 

Stain for Edges of Brown Boots.— To make this, 
get a pennyworth of burnt sienna in water, and 
mix it with water; shake well before applying to the 
edges of the boots so as to get an even stain. Put it 
into two small bottles, say tworthirds in one bottle and 
the remainder in the other, with equal parts of water ; 
this will give two shades of brown. 

Hoisting the Materials for a Tall Chimney.— 

The usual method of hoisting the materials for a 
tall chimney in course of construction is to have out- 
side the foot of the chimney a steam crab or winch, pro- 
vided with a wire rope of sufficient length to reach to 
the top of the chimney and down again— about 400 ft. in 
length for a chimney 160 ft. high. In the base of the 
flue, a snatch-block is attached to a rail, or a rolled joist 
is built in. As the chimney is carried up, a couple of 
rolled steel joists are laid across the flue, on which is 
laid a plank floor, with a square opening in the centre 
for hoisting through, and three shear-legs with pulley- 
block are erected. The brickwork is carried up about 
9 ft., and two other steel joists are laid across, the shear- 
legs being dismantled and refixed at the higher level, as 
is also the plank floor. When the next stage is reached, 
the first two joists are taken out and refixed at the 
higher level, and the shear-legs again moved, the opera- 
tion being repeated every 9 ft. or so until the top of the 
chimney is reached. 

Producing Squeak for Punch and Judy Perform- 
ances. — A penny squeaker is used to produce the 
peculiar squeak by professional Punch and Judy men 
for their performances, but, as a rule, these instruments 
are too large and roughly made. Pronounce the 
word "cow" or "come," and notice where the hinder 
part of the tongue touches the roof of the mouth. This 
is where the Instrument must be placed, and held in 
position by the tongue pressing it against the palate, 
while the .front portion of the tongue, the lips, ami 
cheeks are left tree to modulate into words the sounds 
produced by blowing through the squeaker. A service- 
able one may be made of two pieces of tin, 1 in. by it in., 
slightly curved, with a silk ribbon, fin. broad, stretched 
tlgntljr between and wrapped round once or twice. The 
whole is tied round with thread. The corners should be 
cut off the pieces of tin, or they will injure the roof of 
the mouth. The silk produces a clean, smooth voice, 
although for open-air performances, where a very loud 
voice is requisite, ordinSiry tape in a larger squeaker is 
preferable. 

Heating Cucumber House,— To heat a glass house, 
size about 10 ft. square, for growing earljr cucumbers, 
a boiler to burn coke, with 3-in. or 4-ln. cast-iron 
hot-water pipes, is recommended. A gas boiler would not 
prove so economical and requires careful fixing to shelter 
it from the wind and weather, which may cause it to 
light back or be extinguished. The Loughborough type 
of boiler, which is supplied with pipes, etc., complete, 
is generally found to be suitable. The pipes have 
expansion joints, and the whole is expressly made for 
amateurs' requirements, no skill being needed in putting 
up the apparatus. The boiler is fixed in the thickness of 
the wall and requires no pit or special provision of this 
kind. If the height of the house averages 7 ft. , then 35 ft. 
of l-in., or 46 ft. ol 3-in., pipe will be required. The pipe can 
be carried along two or three sides, below the glass, 
where the house is expected to be coldest. 

BemoTlng Stain and Varnish from Furniture.— 

To each bucketful of freshly slaked hot lime, add about 
21b. of common washing soda. Apply liberally by means 
of old brushes. Carved portions may be cleansed by 
making the mixture into a paste by adding more lime 
or sawdust. Spread this over by means of a palette 
knife. Several applications may be necessary. SwUl 
off with clean water, and finally wipe over with common 
vinegar to neutralise any trace of acid left in the wood. 



86 



Cyclopaedia of Mechanics. 



Solutions for Etching on Brass.— A reliable solu- 
tion may be made by diaaolving nitric acid in about 
flye times the quantitj; of water. Another solution is 
made by mmug a solution of nitric acid and water (1 to 
10 parts respectively) with about an ectual quantity of 
potassium chloride dissolved in 16 of water. A mixture of 
nitric acid 20 parts with 1 of muriatic acid, may be used, 
or a solution containing equal quantities of nitric acid 
and water and a few small pieces of copper may be tried. 

Jewel Case with Secret Drawers.— The following 
instructions tor making a jewel case with secret drawers 
refer to one about 12 in. by 10 In. by 8 in. Pig. 1 Is a 
view of a jewel case when open ; the carcase is put 
together with secret dovetail and mitred joints. The 
front or flap is mitre clamped and veneered on the 
face ; the four drawers which the case contains are all 
hidden. The front AB (Pig. 1) is made in two parts, 
and represents the fronts of five drawers, A being made 
the height of drawers C, D, and E, whilst B Is the height 
of drawer r and tray G. The bottom of G is a fixture, 
as are also the divisions between drawers PE, ED, 
DC; the front A is made as shown, with two scratch 
beads at equal distances. The bead M, which divides the 
front, is loose ; to it are fixed two steel forks, which fit 
Into the square mortises (Pig. 3) ; the two drawer knobs 
K K (Pig. 2) have a small square spindle attached, over 
which the steel fork passes, and fixed on the end of the 



is not exactly correct i for Instance, suppose we have an 
absolutely correct standard acid, and we then make a 
standard soda solution which is rather too strong, in- 
stead of diluting it to the correct strength, we may use 
it as it is, and multiply the results by a " factor." Sup- 
pose 10 c.c. of the standard acid requires 9 c.c. of the 

soda solution, then the latter is ^ = I'll times too 
strong J the figures I'll constitute the " factor." 

Laying Concrete Floor. — Although some experts 
recommend that, for stability, a concrete floor should 
be laid lin three layers, the upper and lower of strong 
material, having the bulk of rougher material between 
them, this plan is not followed to any great extent, 
and the utility of the intermediate course is doubtful. 
In order to make a strong homogeneous concrete, 
the voids in the aggregate must be filled with some 
finer material; it would be an improvemant if the 
material intended to form the first two layers were 
incorporated and laid as one. The finishing coat 
may, it desired, follow closely upon the laying of the 
rougher material, but it will be better it the bulk is 
allowed to set first ; and three days afterwards will be a 
very suitable time to finish off the floor, provided there 
is no need of hurrying the work forward. After 
the fine stuff has been ruled oft, as soon as the 



I 




G> 




e 


O 


ffl 


M °. 


OQ 




Oe 


e 


<t 


D 


s 










FIG. 2 



Jewel Case with Secret Drawers. 



Bpindle is an iron tongue and nut forming a turn-buckle. 
When the knob is turned so that the front is fixed, the 
fork K is dropped and fixes the front A, and, until lifted, 
the latter cannot be moved. N N are dowels fitted into 
the bottom of the ease ; the front B is made to work on 
pivots J J and is fixed by springs HH (Pig. 2). These 
springs are hidden by the silk lining of the tray, and, 
until released, the front A will not move; when the 
springs are released the front will fall on the bottom of 
tray 6, giving access to the bead M. In a shallow case 
it will be necessary to form the movable knob at 0, 
or the forks L L will not draw out sufficiently to release 
the front A. 

Glazing Tobacco Pipes.— For a glaze, dissolve 1 part 
of acetate of lead (sugar of lead) in 5 parts of water, and 
dip the pipes into the solution or apply with a brush ; 
then, after drying, fire at a low red heat. Another glaze 
is made by melting together in a crucible 1 part of car- 
bonate of potash and five parts of borax; pour the 
melted mass into an iron plate, powder it very fine, and 
mix with turpentine. Apply the wash with a brush and 
fire as above. 

Standard Acid and Alkali Solutions. — Standai-d 
acid and alkali are solutions of an acid or alkali 
the exact strengths of which are known. The usual 
standard solutions are the "normal" and the "deci- 
normal." The normal solution of hydrochloric acid 
contains 36'.5 gram, hydi'ochloric acid in 1 litre ; the decl- 
normal contains one-tenth of this amount. The strength 
of a solution of an acid or an alkali is determined by 
measuring, say, 10 c.c, and titrating with either alkali 
or acid, as the case may be, and using some indicator, 
such as litmus, which changes colour when the point of 
neutrality is reached ; the standard solution is dropped 
in from a burette, and when the titration is finished, the 
amount of standard solution used is read off, and from 
this it is easy to calculate the amount of acid or alkali 
present in solution. A " factor " is sometimes used for 
cnloulation when the strength of the standard solution 



surface begins to get firm, is the proper time to com- 
mence finishing-ofl! ; if this is commenced too soon, an 
unequal surface will result, whilst if the stuff is left to 
get too firm, the surface will be rough and patchy. A 
hand float should be used at first, and with this the work 
should be beaten lightly, or patted until the " fat 
appears ; then trowel oft with light strokes until the 
desired face Is obtained. 

Preparation Used by Fire-eaters.— The preparation 
used by so-called fire-eaters to make the skin resist the 
action of fire is strong solution of calcium chloride which 
would remain moist on the skin and protect it to some 
extent. The fire Is obtained by burning a small quantity 
of the lightest naphtha. This rapidly dies out, and pro- 
duces but little warmth. This naphtha is often poured 
on tow and ignited, but the flame at once dies out 
when placed inside the mouth. 

Boiled Oil as a Damp Preventer for Brick Walls, 
—Boiled oU has been highly recommended as a cure for 
dampness caused by absorptive bricks. Its efficacy is due 
to the fact that it fills the pores of the bricks. It 
should be applied boiling hot, and rather lavishly, mth 
a large paint brush or even a Turk's head brush. A dry 
summer day should be chosen, and If possible, a time 
when the wall is warmed by the sun. The coating 
should be renewed every two years. It may rather dis- 
colour the brickwork if the facing is new stock or terra- 
cotta bricks, but will hardly be perceptible with old or 
common work. A small area should be tried at first, so 
as to afford some idea as to the ultimate appearance of 
the whole. 

Re-enamelling Bath,— To re-enamel a hot and cold 
water bath, specially prepared enamel paints are used. 
Thoroughly clean the sui'f aces of the baih wi th petro- 
leum and well scour rusty places with emery cloth ; when 
clean and dry, rub in a paste of lime and petroleum; 
wipe this off before painting. Apply two thin coats of 
paint; allow the first coat to dry hard before applying 
the second. Pale green or eau-de-nil are good tints. ' 



Cyclopaedia of Mechanics. 



87 



Printing Photogrraphs on Fabrics. — There are 
several methods o£ printing photographs on fabrics. The 
simplest is the platinotype, as the material— silk, satin, 
linen, calico, etc. — is supplied sensitised and ready 
for use by the Platinotype Co. It Is treated in the same 
way as paper, being printed to the required depth and 
developed hy Immersion in a saturated solution of oxalate 
ot potash or in the D salts supplied by the company. It 
is ttxed by immersion in one or two baths of hydro- 
chloric acid— strength 1 in 60— and merely requires half 
an hour's washing in running water. A very permanent 
image which will stand washing may thus he produced. 
The prepared material is somewhat costly, therefore the 
following plan may be preferred. Procure some pure 
silk- not treated with acetate of lead— and immerse tor 
two or three minutes in a salting solution prepared as 
follows : Boil 2 dr. of arrowroot in a little water and 
dissolve and add 75 gr. of chloride of ammonium and 
make up to 32 oz. of water and filter. When the silk is 
dry, a sensitising solution of silver nitrate 40 gr., citric 
acid 11 gr. , water 1 oz. Is brushed over It, the fabric being 
pinned flat on a board. Print as usual, but very deeply, 
and tone with water 5 oz., sodium acetate 7 gr., chloride 
of gold 3i gr. Allow this bath to mature for twenty-four 
hours before using it. Very pleasing results are obtained 
by merely fixing without toning. Well wash before 
toning, and place in a bath of common salt and water 
before fixing in hyposulphite ot soda 2oz., water Ipt. 
The pictures may be coloured with crayons and a very 
beautiful effect produced. The crayons may be fixed by 
spraying with a solution of rubber in benzole. The 
picture, if not coloured, may be washed in cold running 
water. By the " Primullne " process prints on a yellow 
ground may easily be obtained in red, scarlet, crimson, 
maroon, orange, brown, etc., by sensitising with primu- 
llne and treating after exposure with a developer. 
In printing fabrics, great care must be taken when 
examining the print lest the material should he stretched, 
when a blurred and distorted image will result. Gauge 
the exposure by experience, or use an actlnometer, 
when the material may be stretched on a light frame. 
Absolute contact must, however, be assured. The grain 
of the material must not be too marked or a coarse 
effect will result. 

Sinking a. Tube Well througb Chalk. — A deep 
stratum of chalk would be penetrated by boring, for 
which purpose a tube of large diameter is necessary. 
A frame, which holds the first length of tube in position 
vertically, is set ov^' the selected spot. The lower 
edge is not sharp, but rough jagged, and the work 
is performed by revolving, the tube by means of a 
portable engine and horizontal pulley wheel on the 
frame through which the tube passes and to which it is 
wedged i a bag of sand placed on the top of the tube adds 
weight when reciuired. When one length is nearly down, 
the boring is stopped and dredging commenced. A 
heavy piece of tube, about 2ift. or 3ft. long and small 
enough to go inside the well tube, has its lower end 
edges slightly sharpened and is fitted with a valve ; a 
small bar is riveted across the upper end, and filed off 
flush outside. To this bar is attached a piece of strong 
cord— that known as " cod line " is suitable. By re- 
peatedly dropping this down the vf ell tube and pulling it up 
and emptying, etc., the borings ai* withdrawn; when 
advantageous, water is poured in. Lengths of tube are 
added as the boring proceeds. 

Welding Cast Steel. — In welding cast steel, the 
flux may consist of borax i lb., washing potash 
ilb., and a srdall quantity of powdered white glass. 
These should be melted together and pounded. Cast 
steel should be kept from the air when heating over 
breeze— not coal— and should not be raised to too high a 
temperature, as it is liable to burn. The blows should 
be light at first. The flux mentioned above should be 
thrown over the surface to be worked before the material 
is put into the fire, more being added afterwards as 
required. 

Cutting Steel Type and Dies.— For steel type and 
die-cutting a considerable plant of tools is required, 
consisting of, for steel -type work, a strong bench, 
heavy vice (about 561b.), an assortment of large coarse 
and small fine files, gravers, hammer and chisels, spring 
dividers, rule, square and straightedge, pump drill, 
grindstone, oilstone, scriber, long pliers or tongs, hand- 
shears, sheet-tin, and cast steel in rod ; and for die-sinking 
work, a die-sinker's vice and hollow pad, chisels, punches 
and matts, curved and straight rifllers, and hand-vice. 
To cut type, first soften a suitable piece of cast-steel rod, 
flle up the sides with a slight undercut, and dress the 
face ; then scribe in the type, or, better still, mark it 
from a tin template. Any round holes In the face are 
drilled with the pump-drill ; the inside work is chipped 
out with lozenge and round-nose chisels ; the outside 
edges are filed in a series of vee-shaped notches to form 
the outline of the type. Finishing is done with gravers, 
holding the work (if long enough to be handled) in the 



left hand, or in a hand-vice against a filing slip 
of wood projecting from the edge of the board, and 
lightly cutting and skimming with lozenge and round- 
nose gravers. Try the work from time to time on soft 
lead or wet clay ; when perfect, put it into a clear coke 
fire, heat to a cherry red, and quench in clean cold water. 
Then temper to a middle brown. Should any further 
. dressing be required, procure some boxwood splints and 
dress off with fine emery and oil. Dies are made with a 
backing ot iron faced with steel, the better to withstand 
the blows ot the stamp. Most dies are either planed 
level top and bottom, or turned in a lathe. In this state 
the blank is screwed up in the die-sinker's vice, and the 
face dressed up with a dead smooth file. A template is 
now placed in the centre of the face, and the shape 
deeply scored with a scriber. The line may then be cut 
round, using hammer and lozenge chisel. If no pattern 
is supplied, a model must be made in modelling wax, 
clay, or plaster-oJ-Paris ; and to get the depth of the die, 
use a sectional tinplate template. After rough chisel- 
ling, use hand-gravers to remove the chisel marks, and 
follow by rifiiers of various curves and contours. The 
die can be finished dull smooth with emery and oil, using 
a light or heavy stick for dressing, according to the size 
of the work. These dies are hardened and tempered by 
the blacksmith who forged them, and then further 
dressed, using a stick, finer emery, and oil. Other dies, 
in addition, require to be burnished with small curved 
steel burnishers, lubricated with ordinary soap and 
water. The various plain and ornamental punches and 
matting tools used by the die-sinker are generally made 
by himself, and it is seldom that the branches of type- 
cutting and die-sinking are carried on by the same 
person. 

Photographing Coloured Pictures. — Coloured 
pictures, or any coloured object, can only be photo- 
graphed successfully by the help of a screen or 
interceptor, which gives the true tone values of the 
colours. In addition, the emulsion with which the plate 
is coated must be specially sensitive to red and orange. 
Such plates (termed chromatic, isochromatic, or ortho- 
chromatic, or colour-correct) may be had ot all dealers 
in photographic materials, those of Edwards being 
particularly good. These plates must be developed only 
in a duU ruby light. Pyro-soda is the most suitable 
developer. The screen may be fixed either before or 
behind the lens, and may either be made by staining a 
sheet ot gelatine in a weak solution ot picric acid, or 

Purchased ready for use. Generally, the screen should 
e a. very pale lemon yellow, but the more the two 
colours named above predominate, the deeper should be 
the tint. 

Making Taps for Watchwork.— Taps for tapping 
screw-holes in watchwork should be made of good steel 
wire. First soften it by heating to a red, and allow to 
cool. Then file to a slow taper and thread it cautiously, 
using plenty of oil. When a full thread has been cut, file 
it triangular, and smooth the flats with a pivot file. 
Harden it by heating to a bright red and plunging in 
oil or water. Brighten the flats with a smooth emery stick, 
and lay the tap on a brass plate held over a lamp fiame 
until the brightened flats show a pale straw colour. 

Red Terra-cotta and Blue Bricks.- The varieties 
ot clay used in the manufacture of terra-cotta are 
the blue, buff, and red clays ot Cornwall, Devon, 
and Dorset, red London clay, and many others. Some 
varieties ot Leeds clays are also employed. These are 
plastic clays, containing a moderate but variable 
quantity of oxide ot iron— from 14 to more than 11 per 
cent. The clay is treated in several ways. In some 
districts it is ground in the dry condition, and then 
mixed in pug mills ; in others it is ground wet to a 
"slip," which is dried to the proper consistency for 
working on the "slip" kiln. It is usual, especially for 
large objects, to mix the clay with a moderate propor- 
tion of ground-baked clay, old pots, ground flint, sand, 
or Cornish stone, in order to prevent excessive shrink- 
ing and warping, and it is essential to allow the 
tempered clay to stand for some time before working. 
The ordinary terra-cotta bricks, facing blocks, orna- 
mental tUes, etc., are machine-pressed, but fine objects 
are pressed in plaster moulds, and the larger objects are 
often built up and modelled by hand. Blue bricks are 
usually made by incorporating " mill cinder " or " iron 
scales " with the clay, the bricks being burnt at a very 
high temperature. 

Lacquering Copper and Brass Candlesticks.— 

Take them to pieces and boil in a strong solution of soda 
to remove old lacquer and dirt. Dip in a weak solution 
of nitric acid and re-polish them. Then make them 
hot in an oven or on a hot plate and brush over with 
pale gold or gold lacquer. Candlesticks may be freshened 
up by brushing them over with a coating of zapon or 
brassoline, which may be procured through a chemist or 
oU and colour stores. 



88 



Cyclopaedia of Mechanics. 



Wiping a Plumber's Underhand Joint. — The 

pipes having been dressed out straight, square the 
ends with a rasp. The horr should be cleaned out ol 
the end ot one pipe, and the outer arris cleaned off (see 
Fig. 1). Open the other pipe-end (Pig. 2) by means ot a 
turnpin, so that the first pipe will enter as far as it is 
rasped off. Clean up with glasspaper and smear the 
pipes with a little whiting or chalk. Now mark the pipes 
at 6 in. from their ends by means ot a gauge (Pig. 3). 
Paint the end ot the pipe as far as the gauge mark with 
warm soil or smudge, and then with a shave-hook shave 
the pipes to a distance of IJin. from the end of the first 
(Pig. J), and IJin. from the end of the second (Pig. 2). 
Shave also the rasped parts of both pipes. They must 
now be rigidly secured in position by laying each pipe 
upon two bricks set on edge or upon two lengths of 
quartering and then holding them down by string as 
shown in Fig. i. On the bench immediately beneath the 
pipes place a sheet of brown paper to catch the solder 
which falls in the process of wiping the joint. Smear the 
shaved parts ot the pipes with tallow, which acts as a 
flux. Bfave conveniently near a pot of solder of the 
proper temperature, and then,, with a ladle in one hand 
and a wiping-cloth In the other, commence to make the 
joint. The first stage is to pour on the metal and " tin " 
the joint, the second is to shape the joint, and the third 



there will be a further decrease in bulk by about 20 
per cent., thus reducing the bulk to about 4 cub. yU. 

Painters' Fillings.— The fillings used tor stopping the 
suction ot wood, plaster, etc., previous to painting, 
may vai^y according to the nature ot the work. A 
very commonly used filler is made from starch by 
incorporating with it some linseed oil and varnish, 
adding a drier, and then thinning with petroleum 
naphtha. The American fillers are made from inorganic 
materials, such as ground silica, steatite, china clay, or 
barytes, and these are ground with raw linseed oU, 
grinding japan, and turpentine or liquid driers. These 
fillers set extremely hard. They are coloured when 
necessary with the usual pigments. A very common 
filler for plastered walls is made by dissolving good jelly 
size in hot water, and thoroughly mixing with it sufficient 
whiting to give it body. 

Wash for Stained Stucco Work.— There Is a wide 
range ot choice in the many washable distempers 
now on the market; but whether any ot them would 
cover defects so as to prevent their re-appearance 
depends entirely upon what causes the stains. If 
they are lichenous growths, an application of dilute 
sulphuric acid will have a beneficial effect in the 
matter of destroying the vegetation, but a deleterious 




Fia 5 



Wiping a Plumber's Underhand Joint. 



and final stage to wipe it smooth. Pour the metal on to 
the shaved part and on about 2in. of the soiled portions. 
Hold the cloth under the joint to catch the surplus 
solder. As the solder runs down the sides of the pipes 
it is caught by the cloth and pressed up against the 
bottom, thus helping to get up the heat and to tin the 
pipes. The joint should be formed quickly by wiping it 
with the cloth, which should be kept at the same curve 
all round the pipe, and pressing the edges so as to get 
them clean. Fig. 5 illustrates the finished joint. 

Quantities for Concrete. — Approximately, the 
voids in gravel, if tree from sand, may be estimated 
at from 25 to 30 per cent, of the bulk, and in 
broken brick or stone at from 40 to 50 per cent, : 
but if it is desired to obtain an accurate estimate 
of the voids in any sample of aggregate, fill some 
known measure with the material, then add water 
until the measure is filled ; the quantity ot water neces- 
sary for the purpose will be the amount ot the voids. 
When dealing with porous materials, the water should 
be measured beforehand, and added to the aggregate 
quickly; subtracting the remainder from the original 
measurement of water will then indicate the extent of 
the voids. But in calculating the amount ot sand and 
cement necessary to till the voids, it must be borne in 
mind that Portland cement and sand both lose bulk 
when water Is added to them, the former by about 10 

fer cent, and the latter by about double this percentage, 
t will thus be seen that the resultant cubical measure- 
ment ot the materials indicated in the question will be 
only about that of the rough aggregate, namely, 5 yd. ; 
and if the concrete is consolidated by ramming, 



effect upon the stucco, the surface of which will be 
more or less disintegrated, according to the strength 
ot the acid. Try the effect of a good brushing with 
a stiff bass dandy; then, for a cheip wash, and one 
that will look better than a white preparation, add 
Portland cement to water in which white copperas has 
been dissolved at the rate ot lib. to 3 gal. Apply the 
mixture, with frequent stirring, in the same manner as 
distemper. A second coat may. If considered necessary, 
follow as soon as the first is dry. 

Papier-mach^ Mouldings.— For making papier-mAohS 
mouldings as need for theatrical purposes, obtain 
some thick, coarse brown paper; tear it into smaU 
pieces 3 in. or 4 in. square, and soak them in cold 
water. Now make some good fiour paste, and while 
hot, to half a gallon of paste add about half a pint of 
linseed oil and about half a pound of melted glue, well 
mix these together. Now squeeze the water from the paper 
and paste each piece thickly on both sides, placing them 
one on the other to keep them moist. These pieces are 
taken up separately and pressed into the mould, which 
need not be filled level, but left hollow so long as the whole 
ot the design is well carried out. Plaster-of -Paris is used 
for making the moulds. The design is first made in clay 
or out in wood. Make a strong box a little larger than 
the model : pour into this box the wet plaster, and press 
in the model, having previously brushed the model over 
with a little sweet oil so that it will not adhere to the 
plaster. When the mould is hard set, line it with oilea 
tissue paper before pressing in the papier-mdohiJ s allow 
this to well set and get partially dry before turning out. 
The mouldings may be fixed with needle-points and glue. 



Cyclopaedia of Mechanics. 



89 



Vanadium.— This is one of the metals of the antimony 
group, and may be obtained as a greyish-white powder. 
It will decompose water at a temperature of about 90° C, 
and does not tarnish in the air. It is insoluble in hydro- 
chloric aeid, but dissolves rapidly in nitric acid and 
slowly in hydrofluoric acid. It burns readily and, in 
a current of chlorine, takes fire. It has been found 
In some iron ores, in copper-bearing beds in Cheshire, 
and in iron slag in Staffordshire. Its symbol Is V, and 
its atomic weight 51'4. 

Heating Greenhouse by a Flue.— In heating a small 
span roof greenhouse, 12ft. by 8ft. by 5ft. to eaves, by a 
flue, the chief points to remember are that the horizontal 
portion of the flue must have a rise of 1 ft. in 10 ft. , and the 
vertical part of the flue at the end of the rise must not 
be less in height than the length of the horizontal part. 
At the base of the vertical part there must be a soot 
door for sweeping, and also to admit of some burning 
shavings being inserted to start the draught, as will 
very Htely be necessary whenever the flre is freshly 
lighted. A small furnace will do, and the flue, built of 
ordinary stock bricks, can be 7 in. by 7 in. Inside. If the 
flue is carried across the 8-ft. end it will do, as close to 
the floor as possible. This wiU give a slightly different 
temperature at the two ends of the house, so that both 
half-hardy and very delicate plants can with care be 
accommodated. 

Curing Goat's Skin.— Trim it on the flesh side with 
a sharp knife, and then well brush with a solution of 
2i lb. of alum and 1 Ih. of common salt in 1 gal. of 
warm water; the skin should be treated two or three 
times with this solution on successive days. Now 
sprinkle bran ail over the skin, brush out, and nail the 
skin to a board and dry it. As a preservative against 
insects, the flesh side of the skin may be treated with a 
mixture of arsenic and black pepper previous to drying 
on the board. 

Inlaying Raised Frets in Finger-board of Guitar. 

—Get a small piece of a bi-oken keyhole-saw, and insert 
it, teeth outwards, in a block of wood ; this will cut a 
groove of uniform depth. The projection of the teeth 
must be correctly determined beforehand. The frets 
may be made of stout brass wire hammered carefully 
so as to partly flatten it. 

Reeds of Organ Pipes.— These consist of a piece of 
hard-rolled brass, fixed by a wedge upon the flattened 
segment of a short cylindrical tube closed at one end, 
as o. This is inserted in a solid block resting in an 
inverted cone of sheet metal (termed a boot) and 
supports a tube which reinforces the tone required. 

Heating Schoolroom.— A schoolroom 66 ft. by 35 ft. 

by 22 ft. high has nearly 61,000 cub. ft. of space in it, 
which, with an ordinary ai'ea of window glass and good 
walls, can be heated by 9 ft. of ^^in. pipe per 1,000 cub. ft. 
of space. This will give 55°F. in very severe weather, and 
80" F. at any other time. If 60° F. is reijuired in severe 
weather, then 10 ft. of 4-in. pipe per 1,000 cub. ft. must be 
allowed. If 2-in. pipe is used, then double the length will 
be required. The advantage of 2 in. pipe is that 2ft. of this 
only holds half the water that I ft. of i-in. does, and this 
means getting the heat up in half the time after lighting 
the flre. If radiators are used, the heat can be got up 
still more quickly, as they hold the least practical 
quantity of water lor a given radiating surface. 

Putting Geneva Watch In Beat.— To see roughly 
where to put the hairspring on a balance so that the 
watch is in beat, af terputtiug in a new hairspring, look at 
the opening in the cylinder ; this should face the 'scape 
wheel. Usually there is a small dot on the balance rim 
against which the hairspring stud should be placed. To 
try finally, see that, when the watch is wound up, the 
baJB,nce when stopped by the finger has no moi-e tendency 
to stop on one side than the other, and always starts on 
immediately it is released. 

Repairing Hole in Boat.— Cut out the plank at the 
part and replace it with a well-seasoned piece, butting 
the remaining parts of the plank over a rib. If thought 
necessary, put in an extra rib or two, if the hole is 
above water-line. An easier method is to push the ed^e 
of a piece of sheet copper under the plank, double It 
over the hole, hammer it close, and tack down with 
plenty of copper tacks ; the part should previously b6 
painted. Cracks may be filled with a putty made of red 
lead, white lead, and copal varnish. 

Soldering Spout on a Copper Kettle.— To re-solder 
a spout on a copper kettle, first thoroughly clean 
the copper where the spout is to be inserted with 
apiece of emery cloth, and also clean the spout around 
Its large end. Then tin' the copper inside the kettle 
where the spout is to be soldered, and also the spout, 
using killed spirits as a flux Pass the small end of the 
spout through the hole from the inside of the kettle, 
and press It up so that the small flange on the large 
end of the spout butts against the side of the kettle ; 



then solder round the spout on the inside of the kettle, 
and leave a thin body of solder floated smoothly round 
where the join occurs, the same flux being used as lor 
the tinning. Solder composed of 14 lb. of tin and 1 lb. 
of lead would be suitable for this purpose. 

Clarifying Glue or Gelatine Syrup. — Decant it 

into a tall tank and let ' it rest for several hours, 
when most of the impurities will settle to the 
bottom, and, after decanting the glue, the bottoms 
may, be added to the next boiling. If a large quantity 
of glue solution is to be treated, the heat contained in it 
will be suftteient to keep it fluid ; but for a small quantity 
a jacketed pan must be used for clarifying. The addition 
of a very small quantity of alum to the glue solution is 
beneficial, as it coagulates the fiocculent matter and 
renders it heavier. For gelatine, moist alumina would 
be suitable as a clarifying agent, or inert white powders, 
such iJs chiua clay or French chalk ; these substances 
should be stirred into the gelatine solution and allowed 
to settle out. Expei'iraents on the lines indicated should 
be tried on a small scale first. 

Repairing Damaged Stonework.— It is presumed 
that the stone from which a piece has been aftcidentaUy 
broken is one of the Yorkshire "grit " stones, similar 
to that obtained from the Howley Park or Idle quarries. 
For mending this kind of stone, mix resin and 
beeswax in about equal parts over a fire, or preferably 
over a hot plate, till both are thoroughly incorporated. 
Pour the mixture into water, and, after it has been well 
manipulated and allowed to cool, make it up into sticks. 
To unite the broken pieces, warm the stone, by means oi 
hot irons, sufficiently to just melt the cement. Apply 
the cement to the fracture, then press tightly and 
firmly till set. This cement, however, ■ has no lasting 
properties when exposed to the weather, but wOl answer 
for internal work. If the piece broken off is not too 
large, use Portland cement mixed with some of the 
pounded dust of the stone, and a little mineral 
oxide to give it the necessary colouring. This will 
make a far more satisfactoi-y and lasting job. 

Proportions of Sand and Lime for Mortar.— 

In mixing lime and sand by bulk, and not by 
weight, it is necessary first to ascertain the cubic feet 
contained in the lime, a cubic foot of which weighs 
39 lb. J hence 5 tons x 22401b. -i- 391b. = 287cub. ft.-, 
multiplying this by 3, it is found that 861 cub. ft. of 
sand wUl be required, the weight of which can only be 
obtained by experiment, pit sand being given variously 
as from 901b. to 1001b. per cub. ft. ; river Thames sand, 
from 911b. to 1021b.j river sand, 1171b. to H81b., etc. 
Thus, with sand at 90 lb. per cub. ft., 344 tons will he 
required; with sand at 1001b., 38i tons; with sand at 
1121b., 43 tons; and with sand at 117 lb., 45 tons. About 
8 tons of water will be required for slaking and mixing ; 
there will result from 45 tons to 55 tons of mortar, 
varying both according to the weight of the sand used 
and the consistency to which the mortar is mixed. The 
exact weight can only be ascertained by experiment. 

Enlarging Photographs without a Camera.— 

The best enlargements are made by utilising a room 
as a camera. The window should be blocked up with a 
screen in which should be cut an opening just large 
enough to be covered by the reversing back of the 
camera ; outside the window, fix, at an angle of 45°, a 
white board or other reflector, which should be about 
three times the diameter of the reversing frame, but if 
the window has a clear view of the sky, the reflector may 
be dispensed with. Adjust the camera against the 
opening, with the lens pointing into the room, and 
insert the slide containing the negative, both shutters 
being drawn out. The picture should be focussed on a 
sheet of white paper or board placed on an upright easel 
or other support, the easel being moved and the lens 
racked out until the proper focus is obtained. Then cap 
the lens, place the bromide paper in position, and expose. 

Autograph Moulds for Rubber Stamps.— To get a 

satisfactory mould, great care lu all the processes is 
essential. Coat a piece of flat metal plate evenly with 
melted beeswax to a depth of about ^in. Before this 
has got quite 'hard write slowly what is required ; make 
the pencil or stylus penetrate to the metal, quite through 
the wax, from end to end of the aiitograph. Clear out 
any shavings or chips of wax that may clog the writing. 
Sift some plaster-of-Pai-is through fine muslin ; dry the 
powder in an oven, making it hotter than the hand can 
comfortably bear. Grind it up with a pestle and mortar 
to remove all traces of lumps, then sift again. Replace 
in the mortar and add enough water to make a thick 
cream, using the pestle to get thorough m.ixture and to 
leave no unwetted powder. Pour the cream upon the 
wax autograph and pat it with a light stick, so as to 
force the cream into the grooves of the writing. When 
the cream has set quite hard there should be a perfect 
facsimile. A similar procedure wUl obtain the true 
mould from the plaster facsimile. 



90 



Cyclopaedia of Mechanics. 



Ink Eraser — One kind is made hj dissolving 1 pai-t of 
oxalic acid in 10 parts of water. Another kind can he 
made by adding 1 part of chloride of lime and i',; part of 
strong acetic acid to 10 parts of water. Oxalic acid is a 
powerful poison, and should therefore he handled care- 
lully. Chloride of lime solution should tafl kept in small 
closely stoppered bottles. 

Thermo-electric Piles.— The simplest form is shown 
in Fig. 1. It consists of a number of strips, say of 
bismuth and antimony. These are joined, and alternate 
.lunctions, as 1, 3, and 5, heated as shown, while the other 
.lunctions are cooled. The action is very weak; for 
instance, for a single pair of these metals the electro- 
motive force is only about 120 microvolts l.-^—- volt") 

\1, 000,000 / 

per degree centigrade difference of temperature between 
the junctions. Even this electro-motive force is lowered 





antimony and lead the potential difference is the differ- 
ence between '000068 and 0, or -000068 volts. The physical 
conditions of the metals have much effect on the voltage ; 
thus, hard platinum is thermo-electrioally negative to- 
soft platinum. A section o( Clamond's thermopile is 
shown in Fig. 2. The elements consist of block A, of an 
alloy (two parts tin and one part zinc), and arms of 
sheet iron F. The latter project and offer considerable 
surface to the air, so that the joints numbered 2, 4, 6, 
etc., to 20 are cooled. The inner junctions 1,3,5, etc., 
to 19 are heated, an earthenware cylinder with holes 
across it allowing coal-gas jets to play on the joints. 
Five such layers were used. Another form of Clamourt 
pile is shown by Fig. 3. In this the hot gases from a coke 
turn-ace 1' pass up through the flues T, o, and P, and out 
at the chimney at A. The elements are shown at (\ 
while copper radiators D attached to the outer junctions, 
but insulated, from them, serve to increase the difference 
of temperature. It is said that from a battery with 
3,000 couples the total electro-motive force obtained was. 
109 volts, the internal resistance being IS'S ohms. The 
temperatures of the junctions were not stated, but 11 lb. 
of coke was burned per hour. 

Pendulum and Rod for Dutch Clock. — The 

pendulums of Dutch clocks only weigh an ounce 
or two, and the bobs are tisually made of turneii 
wood about 2 in. diameter and i In. thick. The rod is of 




Fig. 2 



Thermo-electric Piles. 



by the " Peltier " effect, and the piles are racked by 
stresses due to expansion and contraction. The follow- 
ing table gives particulars of the thermo-electric pro- 
perties of some metals, the electro-motive forces given 
being those obtained by junctions of the particular 
metal with lead, the difference of temperature being 1° C. 



Miinh. 


Electro-^inotive 
Force. 


Metals. 


Electi'o-vwtive 
Force. 


Bismuth ... 
Nickel ... 
German ' 
silver 1 
Aluminium 
Tin 


+ -000068 volts 
+ -000024 „ 

+ -00001.5 „ 

+ -0000006 „ 
+ -0000001 „ 


Lead 

Copper ... 
Silver ... 
Zinc 
Iron 
Antimony 


- -0000017 volts 

- -0000029 „ 

- -0000035 „ 
-•000015 „ 

- -000046 „ 



The cuiTent flows from the metal that is higher on the 
list; thus, comparing bismuth and antimony, from the 
flrst to the second. The value of the electro-motive force 
for any pair of metals is the algebraic difference of the 
numbers given in the table ; thus, of bismuth and 
antimony it is the difference between + '000068 and 
- -000046 = '000068 + '000046 = '000114 volt, and between 



iron wire, hammered flat at the top end and turned over 
into a hook. This is hung on a wire loop at the back of 
the clock for a suspension. The usual length is from 
24 in. to 28 in. One should be made full length, and then 
shortened until correct. There need be no regulating 
nut, the wooden bob merely sliding on the wire rod 
friction tight. 

Colouring Matter Used for Gelatine Photographic 
Films. — The colouring matters used depend on 
the purpose for which the plates are requii'ed. Eosine, 
alizarine blue, ceriiline, etc., are employed. Eosine is 
generally used for isochromatic plates. This colour 
fades in direct sunlight, but would not do so in the 
fraction of time required for exposure. 

Dry-cleaning Valencia -Waistcoat. — To drycleau 
a striped Valencia waistcoat and lining, out 2oz. of 
Sunlight soap into shavings, and pour over it IJ pints 
of boiling water in which is placed a small piece 
of alum. Beat this into a lather and leave to cool. 
When cool it will be the substance of a jelly. Apply this 
to the waistcoat with a close sponge ; do a few snuare 
inches at a time. With another sponge, wash off the 
substance with a very little tepid water. Then saueeze 
the water from the sponge and dry the material. Repeat 
this process till the vest is finished. Then hang it up 
until thoroughly dry, and dry-press. 



Cyclopaedia of Mechanics. 



91 



Iilntng Out Cart Wheels.— When lining out a cart 
wheel one of the best ways is to tilt the horse hack, by 
patting a block underneath the front part, to any angle 
required (being careful not to overdo it, or wheel and 
horse will overbalance), then gently revolve the wheel, 
gauging the lines on in the usual manner. By this 
method there is not so much chance of getting jumps 
In the lines as when done on a box. The fronts of the 
spokes can also be done when in this position; the 
stock should be done with the wheel on the horse in its 
ordinary position. If, after lining the surface, it Is 
ilneven, take some glasspaper and ciit down the ridges 
caused by the lines, and give another coat of paint. The 
prices of colours vary according to quality, but for 
experimenting a green Is, best ; this can be mixed to so 
mansr shades, and various colours In lines blend well 
with it. 

Making Opaque Coloured Glass.— Opaque glass or 
enamel may be made by adding white insoluble 
substances to the ordinary flint or soda glass while 
it is in a melted condition. Bone phosphate or bone 
ash and barytes are most commonly used, but cryolite, 
white arsenic, and oxide of antimony ai"e also em- 
ployed. To render the glass dull, add to it as much as 
possible of either bone ash or barytes consistent with 
proper working and to keep the temperature high while 
it is stirred into the glass. The colours used are the 
same as for transparent glass, but more colouring 
matter is required to give intensity on the white base. 
For blues, cobalt oxide, smalt, or black oxide of copper 
are employed ; for violet, oxide of manganese ; for ruby, 
oxide of gold, suboxide of copper; for emerald green, 
copper oxide and oxide of iron, chromium oxide (chrome 
green) ; for yellow, uranium oxide, oxide of antiifaony, 
etc. 

Ink-pad for Rubber Stamp.— To make a pad, cut 
from the lid of a cigar-box a piece of wood of the 
desired size. Upon this place several thicknesses of 
sheet-cotton cut to size. A stretch of fine woollen 
cloth and a top or surface of linen (a piece of an old 
handkerchief Is excellent) is now put on. The two 
latter coats must be long enough to come well over the 
wood round the edges. Finally, tack on a binding of 
leather or tin. If a lid of a tin is handy, it is a good 
plan to make the pad to fit into it. 

Making Painters' Knotting.— To make a gallon of 
knotting, as used for painting knots in new woodwork, 
i lb. of powdered shellac is dissolved In li gal. of 
methylated spirit ; to do this, place it In a warm place, 
and frequently agitate it. Made this way, It will require 
shaking up before being used. This is the patent knot- 
ting of commerce, to which, however, something is 
added to keep the shellac in solution. It will not pay to 
make it, patent Jinotting being much superior, where 
patent knotting is not available, French polish will 
answer the purpose of stopping-out the knots. 

Length and Weight of Clock Pendnlums There 

is no rule as to the weight of a clock pendulum; it 
is regulated according to the quality of clock. The 
best clocks cari-y the heaviest pendulums. Weight 
does not affect the time of vibration ; that depends 
solely on the length. There is no formula for determin- 
ing the friction or resistance to the air of a pendulum. 
To find the length of a pendulum for any given clock, 
first find the number of vibrations it Ls required to 
make in one minute, and then find th0 length of a pen- 
dulum making that number either from a table or by 
calculation. To find the required number of vibrations 
per minute, multiply together the numbers of the teeth 
in the centre wheel, third wheel, and 'scape wheel. Divide 
this by the numbers of the third pinion and 'scape pinion 
and 30. Thus, suppose the centre wheel is 64, third 
wheel 60, pinion 8, 'scape wheel 30, pinion 8, then 
64 X 60 X 30 „. , . .-u J.- -4. 

8 X 8 X 30 ' = 60 = number of vibrations per minute. 

To find the length of the pendulum making this number 
of vibrations per minute, divide 375'4 by the number and 

375*4 
square the result. Thus -jg- = 6-26 ; this squared = 39'18, 

which is approximately the length of the seconds pendu- 
lum in England. 

Pipes Keptuired to Heat Drying-room by Steam.— 

The quantity of pipe required depends on the pressure 
of steam available. With a low pressure, say 101b. 
per square inch, to obtain 150° Fah. 150 sq. ft. sm-- 
lace of steam pipe per 1,000 cub. ft. of space will be 
wanted. The room has just over 10,000 cub. ft. of space 
in it, and therefore requires 1,500 sq. ft. of heating 
surface, or, say, 2,860 ft. of 2-in. pipe. , This is supposing 
the ventilation to be free. With high-pressure steam, 
considerably less pipe will suSBce. A single 2-in. pipe 
all round would scarcely suffice to heat the room 55 
OTthout the full degree of ventUation that is needed in 
drying-rooms. Wrought-iron pipe should be used. 



Dyeing Light Cloth Black.— Put 10 lb. of loswood 
and 31b. of bruised galls in 3 gal. of water ; Boil for 
two hours, and strain. Place the coat in the dye, and 
allow it to remain for half an hour. Take it out, and add 
about 21b. of copperas. Replace the garment, and boU 
till the dye has thoroughly impregnated it; the time 
this will take depends on, among other things, the 
quality and original colour of the coat. Kemove it, and 
hang up for an hour ; then rinse it twice, or three times, 
in cold or slightly warmed water, and dry. Bometimes 
a garment requires a second or a third dipping. Finish 
by pressing into shape. Common or old cloth will not 
stand much boiling, and pure woollen goods have to b» 
treated with extreme care. 

How to Preserve Blown Eggs. — To prevent 
birds' eggs cracking or crumbling after they are 
blown, well rinse them out with corrosive sublimate 
dissolved in spirit of wine (a few grains to the 
ounce) ; this is a deadly poison. Insert a small 
quantity into the egg by means of a glass egg-blower 
with a bulb, then shake the egg so that the solution 
comes into contact with all the inside skin. Now draw 
the solution out of the egg by the blower, and return it 
to the bottle. Now place the egg with the hole resting 
Upon blotting-paper, so that the last drop or two may be 
drawn out, and finally cover the hole with a small piece 
of gummed paper. Water containing a few drops of oil 
of cloves may be used in place of the sublimate if 
desired. 

Concrete to Cover a Brlofc-paved Floor.— The 

materials used should be broken bricks, clean sharp 
sand, and Portland cement, in the proportions of 
6 parts aggregate to 1 part cement. An area 16 ft. by 
14 ft. by 2 in. contains 34 cub. ft., or about Ucub. yd. 
The quantities required will be about I cub. yd. of 
broken bricks of the size of a walnut, 1 cub. yd. of 
sand, and ^ cub. yd. of cement, or say about 7 cwt. 
These materials should be well mixed together in a dry 
state, a minimum quantity of water applied from a 
water-can with a rose nozzle, and carefully laid to the 
desired level, being worked with a trowel until the 
cement creams on the, surface and the whole is even. 
Only a small quantity should be wetted at one time, 
and before a start is made the existing brick floor should 
be well brushed with a stiff brush, until all dirt, moss, 
etc., is entirely renioved and the bricks are clean. 

Cream-coloured Paint for Table Oilcloths. — For 

a paint for table oilcloths, try white lead or zinc 
white ground in oil, with 4 oz. of patent driers to the 
pound, and enough boiled linseed oil to make it flow. 
This paint should be applied in a warm room and dried 
I'apidly while hung in a room heated by flues running 
along the floor. The cloth should previously be coated 
either with a thick boiled starch or with glue size. 

^ow to Make Sarsaparlll:^ Beer.— Dissolve li oz. of 
compound extract of sarsaparilla in 1 gal. of hot water, 
and vrheu the solution is complete stir in 2 lb. of 
moist sugar. When the liquid is lukewarm, stir in a 
wineglassful of brewer's yeast and keep in a warm place 
overnight. Next day, skim off the yeast, strain the 
liquid, and bottle : tie down the corks, and leave for a 
week to become brislr. Instead of the extract, i lb. of 
sliced sarsaparilla root may be used, but this will have to 
be boiled with the water ; 1 oz. of liquorice root and i oz. 
of aniseed added to the beer are considered by some an , 
improvement. 

Bbonising Pine.- To ebonise pine, take 1 gal. of water, 
lib. of logwood chips, ilb. of copperas, i lb. of extract of 
logwood, 2 oz. of indigo blue, and 2 oz. of lampblack. Put 
into an old iron pot and boil slowly. When cold, strain 
through canvas, then add ioz. of powdered nut galls. 
Or take I gal. of vinegar, 2 lb. of extract of logwood Jib. 
of green copperas, 2 oz. of China blue, and 2 oz. of nut 
galls. Boil over a slow fire. Give at least two coats with 
an old brush. When dry, intensify the black by brushing 
over with iron solution, made by steeping a good hand- 
ful of iron filings or rusty n ails in 4 pt. of vinegar ; smooth 
down with glasspaper, then fill in the grain with a filler 
made of finely crushed whiting, lampblack and turps 
made into a stiff paste; finish with polish— to make 
which add to 1 pt. of methylated spirit 4 oz. to 6 oz. of 
best orange shellac and i oz. of black aniline spirit dye. 

White Ground for Drawing Boards To obtain a 

white ground on drawing boards so that drawings made 
with charcoal and coloured chalks may be easily rubbed 
out, mix dry white lead to a stiff paste with gum arable 
dissolved in water; add water till it works easily, like 
paint. When applying it, either stipple it with a hog- 
hair brush or cross and re-cross it till no brush marks 
are seen. A little of the white should first be tried on 
the corner of the board. Let it dry, then rub the fingers 
over it. It it rubs off on the fingers, add more gum ; if it 
shines, there is too much gum. To dissolve the gum,, 
saturate it with water and stand in a warm place. 



92 



Cyclopaedia of Mechanics. 



Matt Surface on Fhotoeraphic Prints. — To 

obtain a matt surface on photographic pi-ints, matt 
P.O.P. should he used, thia giving the finest results. 
But a matt surface can be given to an ordinary glazed 
print hy squeegeeing it on to the rough side of a piece of 

f round glass, the mode of procedure being the same "as 
hat for producing a highly glazed surface on ordinary 
glazed P.O.P., substituting ground glass for the ordin- 
ary glass or other polished surface. 

Determining Po\rer of Engine from Indicator 
Diagrams, — To calculate the horse-power of an 
engine from diagrams, each diagram should be marked 
off, as shown, by ten lines perpendicular to the 
atmospheric line AL. The extremities of the diagram 
are marked on the line AL and the distance between 
divided into twenty equal parts, perpendicular lines 
being erected at the first division, third division, fifth 
division, and so on. The diagram cuts each of these 
lines in two points, and the distance between these 
points should be measured to obtain the effective 
pressure shown by the card at that line. This, however, 
is not the effective pressure on the piston at that point in 
the stroke ; to obtain this the two cards, front and back, 
must be superposed, and vhe back pressure shown on one 
deducted from the f orwai d pressure shown on the other. 
This, however, has no effect in the mean pressure as 
obtained below. The pressure as obtained from the 
diagi-am depends on the spring used. On cards with 
which a jV spring is used a length of lin. shows a 
pressure of 401b. per square inchj so that a length of 




Determining Power of Engine from Indicator 
Diagrams. 

It in. on the diagram would indicate a pressure of 
18 X 40 = 651b. per square inch. Owing to reduction, the 
actual scale of the illustrations is A. or lin. = 801b. per 
square inch. , Measured in this way, the pressures are, 
commencing from the left in Pig. 1, 68, 80, 60, 50, 40,324, 25, 
lei, 15, and 101b. per square inch, and, in Pig. 2, lOi, 15, 20, 
25, 30, 35, 45, 55i, 77i, and 72i. The mean of each of these 
is their sum divided by ten. Thus the mean pressure 
shown by Pig. 1 is ?^ 

by Fig. 2 is 



10 



91b. per square inch, and 
= 38'6 lb. per square inch. The mean 
pressure during the two strokes may therefore be taken 
at 39"0 + 38-6 ^ 39.35 n,. per square inch. The horse-power 
may now be determined. 

Flat-flame and Bunsen Gas Burners Compared.— 

Comparing the heat given off by gas burnt in an ordinary 
ga»-burner and that burnt in a Bunsen burner, Pro- 
fessorLewes states that aluminous flat-flame burner gives 
a temperature of ^,462° P., and an ordinary Bunsen flame 
a temperature of 2,732" P., while by increasing the 
quantity of air until the flame is on the point of flashing 
down the tube the temperature rises to 2,966° P.; in ten 
experiments the amount of gas consumed is not stated. 
A Bunsen burner consuming 4 cub. ft. per hour will 
require about 36 cub. ft. of air per hour, while the air 
would be contaminated to the same extent by both 
descriptions of burner, since the total amount of gas 
burnt and consequently the products of combustion 
given off would be the same in both cases. When the 
igaa is mixed with too much air It forms an explosive 



mixture. With regai-d to the proportioning of the gas 
and air supplies of Bunsen burners, the information on 
this point is mainly due to the labours of Mr. T. Fletcher, 
P.O. 8., the well-known gas-stove maker of Warrington. 
In a paper read before a meeting, of the Gas Institute in 
1888, Mr. Fletcher states "that the mixing-tube [of a 
Bunsen burner] it horizontal should not be less in 
length than four and a halt times or more than six times 
its diameter." With regard to the diameter of the 
mixing-tube, " with large flames, given a certain size of 
gas jet, the diameter of the mixing-tube should not be 
less than ten times as great." " Given a certain area of 
tube delivering a combustible mixture, the outlet for 
this mixture must be neither more nor less than the 
size of the tube." " The variation from the rule, how- 
ever, must be a matter of experience with each form of 
burner. There is also \he fact that with small divided 
flames it is not necessary to mix so lai'ge a proportion of 
air, as each flame will take up air on its external surface: 
but in this case the flames are longer, hollow, and of 
lower temperature. As a matter of actual practice, 
where a burner is used which givesa number of separate 
flames or jets the diameter of the mixing-tube does not 
need to exceed eight times the diameter of the gas jet, 
the remainder of the air required being taken up by the 
surfaces of the flames." It wiU be seen from tne fore- 
going that it is advisable to regulate the air openings 
according to the quantity of gas passing. 

Catch for Fastening Door of Street I>amp. — 

The diagrams show a catch suitable for a large 
lamp. Pig. 1 is a front elevation of the angle iron 




Catch for Fastening Door of Street Lamp. 



forming the bottom of the door, with a small rectangular 
box riveted upon it, in which a flat bolt is arranged, so 
as to slide up or down. Pig. 2 is a plan of the T and angle 
iron, box with slot in top and opening at bottom, and 
also an iron plate riveted on the underneath side of 
T-iron, a slot being cut in this tor the bolt to slip into to 
fasten the door. Pig. 3 is a section on the line A B, show- 
ing the position of bolt in box, and projecting plate 
on T-iron with slot for bolt to eutei^. 

Use of the Box Sextant In Surveyiog.— The box 

sextant is an instrument about Sin. in diameter, to be 
held in the hand, tor ascertaining approximate angles 
between any given stations. It is made with or without 
a telescope, and is in general appearance like Fig. 1. 
An enlarged diagrammatic plan is shown in Pig. 2, 
where A is the sight hole of the telescope ; B is a 
fixed glass, the lower half silvered and the upper half 
plain ; c is a mirror attached to the same pivot as the 
vernier arm D. The side of the case is open at E and S , 
to admit the rays ot light from the observed objects. 
The required angles may be between station poles, 
church spires, or any other deflnitOi lines or points. 
"i'PPPf ®,^ single pole be looked at, the angle indicated 
should be 0" or zero ; whether it will actually be so 
or not depends upon circumstances which the follow- 
ing remarks will explain. Suppose a pole to be fixed at 
G, which, bearing in mind the scale, would be abnormally 
close. It can be seen through the clear part ot the glass 
atB on applying the eye to the sight hole at A. At the 
stoe time the rays of light from the pole G will be 
streaming in all directions, and some ot them will pass 
along the dotted line direct to the mirror C, and, when 
the vernier arm is placed in the position shown by the 
dotted line, the rays of light will be reflected to the 
Slivered part ot the glass B, and from thence to the eye 
at A, the appearance being as of one continuous pole 



Cyclopaedia of Mechanics. 



93 



f; 



down the two parts of the glass. If the vernier he now 
examined, It will be seen that the broad arrow falls 
short of the zero of the scale owing to what may he 
called the width of base line of the instrument. If the 
■lole be placed farther off as at H, the rays of light 
oUowing the stroke-and-dot line will require the vernier 
arm to he shifted rather nearer the zero of the scale- 
but until the pole is at a distance of two chains from 
the observer there will be a similar error of less and. less 



' H 

i 




Sow to Use the Box Sextant. 

amount. Between two chains distance and an infinite 
distance the rays bf light from the pole to B and are now 
BO nearly parallel that the error is under one minute of 
arc, so that the instrument can be used without difficulty 
under those conditions. It is usually adjusted by 
sighting it to the sun, which should appear through the 
smoked glass as a perfect sphere in whatever way the 
sextant may be held when the vernier is at zero, when 
an angle is to be taken at one station and between two 
others, the nearer station should be viewed through the 
plain glass, so that the sextant may need to be held 
upside down. When the angle to be read exceeds 
90", an intermediate pole should be set up and the 



anglfes taken in two portions, as In viewing large angles 
the mirror is moved so far i-ound that its reflection, 
and that of the image it carries, is viewed almost edge- 
ways in the mirror at B. The vernier arm is moved by 
means of a mUled head screw on the top of the case. It 
should be noted that the box sextant only gives angles 
in the plane of the instrument, so that if the stations 
observed are not on the same level, the angle given will 
be the direct angle between them, and not the horl. 
zontal angle such as would be given by a theodolite. 

How to Make an Sverset Photograpbio Shutter.— 
A shutter suitable for use with a single lens at the 
diaphragm (as employed in the bull's-eye kodak, and 
shown complete at Pig. 1) may be made as follows :— Cut 
thin brass or zinc to the shape shown by Fig. 2. The 
centre part A is punched in, and upon it the shutter or 
circle turns. The projections are turned up, and the part 
E, after beihg pierced and out round, is turned up on the 
dotted line. Wow cut the releasing arm (Fig. 3) in the 
metal, bending in the dotted lines to the form J. Note the 
slot L. Around the screw or pin fitting the screw hole M 




How to Make an Ererset Photographic Shutter. 

goes one end of the steel wire shown in Fig. 1, which passes 
from it through O across L, and very loosely through the 
large hole in B. The fixing of the shutter is shown 
in Fig. 1, and when attached to the camera front by a 
broad-headed screw through D and another at Z, the catch 
P is fixed in the correct position. Through the arm the 
wire pulls the shutter round when out of the way of pro- 
jection Q or G. As the shutter stands away from the front, 
space is left for the diaphragms between it and the lens. 
These consist of three holes formed in the triangular 
plate E worked by the arm S and guided by the semicir- 
cular piece T. The position of the first audlast diaphragm 
is governed by the slot TJ, hut the middle one is centred 
with the lens by having a dent T' in E, which receives 
a similar projection (the under part of the dent) in T. 
For tilne exposures the arm V (Fig. 1), also shown at Fig. 
4, is lifted, the slot W passing around the screw X, and 
when raised it meets the projection F, and, on pressing the 
release in the opposite direction, it returns. Projections 
H and I then come into use. The method of bending 
the arm may he gathered from Fig. 1, which shows the 
shutter set for an Instantaneous exposure, it having 
travelled halfway. 



94 



Cyclopsedia of Mechanics. 



Method of Hinging Screen Frames.— It Is often 
difficult to decide which is the test and cheapest way ot 
hanging screen frames. A screen should be hinged so that 
It will close both ways, but the expense of the double 
folding joints made specially for that purpose Is too 
great to admit of their frequent use. The following 
describes a cheap, simple, and efficient substitute. 
Assuming that the frames are ready for hanging, and 
that the screen consists of four frames, there will be 
three separate hangings, which will require six laths 
laced together In pairs, as shown. The laths should be 
sawn out ot a i-ln. board the full height of the frames, 
and if the thicliness of them is I in., the laths should 
be A in. wider, to allow the screen to close flat together 
without any strain. Gauge and plane up the laths 
both in width and thickness, neatly finish oft the 
ends so that all of them are exactly the same length, and, 
to prevent the sharp edges cutting the tapes, rub them 
well oft with sandpaper. They are now ready for paint- 
ing, staining, varnishing, or polishing, as may be pre- 
ferred. When they are dry, proceed to put on the tape, 
which may be got in various colours from Jin. tolin. 
wide ; about 3yd. will be required for each pair ot laths. 
Mattress binding is good j being made of lin en it does not 




Fig. I Fic. 2 

Hethod of Hinging Screen Frames. 

stretch. Begin by tacking the end of the tape to the top 
end and under side of one ot the laths in an oblique direc- 
tion ; lay the two laths together, pass the tape up between 
them from the under side, and lace them together rather 
loosely, over and under, first left, then right, and leaving 
a loop as shown at Fig. 1. When sufficient turns have 
been put on to reach the bottom, begin again at the top 
to pull the laths tight together, turn by turn, and 
regulate the distances ; fasten the end off at the bottom 
to the underside, as before. It is of great advantage to 
hold the two laths edge to edge in the bench-screw while 
pulling the tape tight, as it leaves both hands at liberty 
to manipulate it. Proceed now to hang the frames 
together ; bore f oiir holes in each lath, at equal distances 
between the tapes, neatly countersink for screw-heads, 
and screw them to the edges of the frames. This 
joint has a very pleasing effect if it is neatly done 
and the tape is made to harmonise with the material on 
the frames. It is very durable, draught- and sight-proof, 
and can, if necessary, be renewed at a very small cost of 
time and money. 

Transferring Photographs to China, etc.— To 
finish off a photograph so that It will look like china 
without enamelling, several simple methods of trans- 
ferring are available. Among these is the use of 
Eastman Transferrotype paper, and various makes ot 
stripping P.O.P., which are to be had of photographic 
dealers. Ordinary P.O.P. may also be used, but the result 
is somewhat uncertain. In the case ot ordinary P.O.P., 
thoroughly wash the article to which the photograph is 
to be transferred, then coat It with a weak solution con- 
sisting ot gelatine 10 gr., water loz., and bichromate of 
PotSish 5 gr. Crush the bichromate, and add the gelatine 
last. Expose the coated side to the light, and wash for 
some hours. Take a very darkly printed proof finished 
and dried, but not alumed, soak it in cold water, and 
then place on the article to be decorated ; squeegee the 
print thoroughly into contact, and dry. Now pour on 



hot water till the print blisters badly, when the paper 
may be stripped away. If the water is too hot, the 
gelatine will melt. Cfreat care must be taken not to 
move the print, which should be laid flat ; and when dry 
a coat ot copal varnish should be applied, and the article 
baked. It will then stand careful washing. 

Boring a Railway Tunnel from Both Ends.— In the 
construction ot railway tunnels it is usual to work from 
both ends, and sometimes from intermediate points also. 
The line of route is laid out on the surface to facilitate 
observations underground; but if this is impossible 
the extreme points have to be connected by accurate 
trigonometrical surveys and exact levels, so that their 
relative positions are precisely known. The centre line 
at formation level is then accurately set out by theodo- 
lites and standard chains, a smaller heading being driven 
in advance of the main tunnel, so that (apart from 
facilities of construction) in the event of a slight error 
in meeting the heading from the other end, the direc- 
tions may be adjusted. 

Garden Tripod Stand for Telescope.— A cheap 
equatorial stand that does not require much lathe work 
in its construction must have an axis on which to 




Garaeu Tripod Stand for Telescope. 

rotate, to provide the horizontal motion ; the vertical 
motion being provided by a metal clasp having two 
trunnions, which rotate on wooden uprights provided 
with V-shaped bearings. This mounting is supported by 
a wooden tripod stand similar to the ordinary camera 
stand, though, of course, more substantial and rigid. 
It can therefore be used either indoors at an open 
window or in the garden. In the tripod shown in 
Pig. 1 the three legs are bolted to a wooden 
base and provided with three cheeks for the purpose. 
Under the base, about halfway down and connecting 
the three legs together, is a sort ot a double joint, 
which folds upward when the stand ig not in use. 
When open, this drops and keeps the legs stationary. 
Above the base, and glued and screwed to it, la a 
circular, cylindrlcally shaped block having a hole 
through its centre to receive a female cone ot metal. A 
recess in the block receives the shoulder at the top, which 
is then screwed down to the block. This cone is shown 
in section at A (Fig. 2) . A cone, shown at B, is similarly 
screwed to the oblong stage of wood above the block, 
to which the uprights are screwed. The two centres 
are ground together, and, when fitted accurately, are 
held together by a screw and washer at the ends. 
The uprights, shaped as in the illustration, carry the 
clasp by its trunnions, the dasp being screwed around 
the body tube of the telescope. The clasp is a metal 
casting about 2iln. deep, wltn two circular trunnions 
and two rectangular wings. This is shown In elevation 
and plan at Pig. 3. When the hole has been turned to fit 
the tube, and the trunnions turned exactly equal to each 
other in diameter and fitted between the uprights and 
to the V's on them, the rectangular wings are drilled for 
four screws, two at each wing. The ring is then severed 
into two halves, the saw cutting through the wings. 
Some blotting paper is then pasted In the curves of each 
halt, to prevent the disfigurement ot the lacquer work 
on the body tube, and, when dry, the clasp is screwed 
together around the tube. In this way the two horizontal 
and the vertical motions are supplied. 



Cyclopaedia of Mechanics. 



95 



Time for Photographic Exposures.— All photo- 
graphic exposures being somewhat in the nature of 
an experiment, because of the ever-varying conditionB 
of the atmosphere, It is possible only ' to give 
approximate times. Over-exposed plates may be cor- 
rected by careful development ; but a very much under- 
exposed plate Is past remedy, and a slow plate is more 
easily dealt Tvith than a fast one. As a rough guide to a 
beginner, exposure meters may be of service, but, if 
followed too slavishly, they may prove worse than use- 
less. The following is the minimum exposure for June, 
11 a.m. to I p.m. :— Clouds, A sec. ; sea and sky, .^sec. ; 
open landscape (distant objects only), Jsec. ; buildings 
(well illuminated), isec. ; groups (light dresses), isec. ; 
groups (dark and heavy contrast), 1 sec. It is impossible ' 
to classify interiors as light and dark to be of any use. 
The only practical plan is to make a trial exposure and 
develop the plate. If it is impossible to develop a trial 
plate, make several exposures of different lengths. In 
aU exposures the colour or the light and the degree of 
contrast in the subject and that required in the picture 
must be taken into account. It may here be mentioned 
that one would hardly attempt clouds, sea, or sky in the 
middle of the day. Bear in mind the old rule, " Expose 
for the shadows, and let the lights take care of them- 
selves." 

Clockwork Metronome. — To make a clockwork 
metronome, a pendulum must be employed. The usual 
arrangement is to have a short lead bob pendulum, 
about 3 izi. long, pivoted upon an arbor. The rod 
is extended upwards, and this upper portion is fitted 




Clockwork Metronome. 



with a sliding weight to adjust the speed. The 
higher the top weight is raised the slower the pen- 
dulum goes. The escapement is shown in the accom- 
panying sketch. The 'scape wheel teeth are straight 
pins, and they rest upon two flat steel discs fixed on 
the pendulum arbor. These discs are cut, and the edges 
bevelled off, to give the impulse alternately In each direc- 
tion. Thus, one of the pins of the 'scape wheel falls 
upon the face of disc A and, passing the bevelled edge, 
gives the pendulum an impulse to the right and falls 
upon the second disc B. As the pendulum returns, this 
tooth gives impulse, by means of the bevel on B, in the 
opposite direction to A, and the next 'scape tooth falls 
upon A, and so on. An American drum-clock train will 
do. The 'scape wheel must be taken away, and the next 
wheel before it converted into a 'scape wheel by breaking 
out some of the teeth, leaving one in every three, and 
bending them forward a little. 

Protecting Exposed Water Mains from Frost.— 

There are incox-rect ideas as to how a bad heat-con- 
ducting, material protects pipes from frost. Water 
absorbs and holds heat, but the heat is readily dissipated, 
or radiated, or becomes absorbed by cold air or substances 
with which it comes in contact, the consequence being 
that its temperature is reduced below 32° and the water 
becomes ice. The purpose of a bad heat-conducting 
material is to form a barrier to this heat transference, 
so that should the water be, say, 50°, the air and general 
surroundings can be much lower in temperature without 
reducing the heat of the water in any marked degree. 
The covering, therefore, does not afford any heat what- 
ever, but prevents heat passing through It. Coverings, 
however, to be as effective as this would require to be of 
materials which are perfect non-conductors of heat, and 
this is not as yet possible. There are some very effective 
bad conductors, almost non-conductors, and the two 
best are undoubtedly hair felt and silicate cotton (slag 
wool). Both vary in effectiveness according to the 
thickness of the covering. If hair felt is used it can be 
i in., but ^ in, is better for good work. It should be out 



in strips and be wound on the pipes soundly ; but it is 
best not to bind It on too tightly afterwards. It should 
be secure, but not compressed. The silicate cotton is 
usually a loose material, and i-equires to be placed in a 
casing. It can, however, be obtained sewn on to canvas. 
Probably any one of the patent compositions used for 
jacketing steam boilers would answer the purpose. The 
coating should afterwards be lagged with narrow boards 
secured with iron belts or bands, or be covered with 
canvas and painted, tarred, or otherwise protected from 
decay through damp or by atmospheric corrosion. 

Simple Method of Copying Negatives for Iiantern 
Slides. — The following is a simple way to make 
lantern slides by reduction, the ordinary camera 
and lens being used, supported preferably on a 
table :— First make a carrier to hold the lantern 
plate in the dark slide by tongueing together, to form 
a frame, two pieces of i-in. wood 4fin. by Ijin., and 
two similar pieces 6iin. by {in. Rebate the inner and 
outer edges on opposite sides I'sin. Thoroughly clean a 
window pane and place the negative for reduction (A) film 
towards the camera in one corner. Fasten In position 
safely with two drawing pins. Outside the window D 
suspend at an angle of i5°, to act as a reflector (0), a sheet 
of white cardboard at least four times the size of the 
negative. Fasten at the bottom and attach string to 
the two top corners. In a large sheet of brown paper 
B cut a hole A just large enough to expose the whole or 
the desired portion of the negative. Pin this up and 
fasten curtains across the top of the window. Build the 
camera up level with the boxes, focus very sharp, and 




Apparatus for Making Lantern Slides. 

expose as usual. The centre of the plate must exactly 
coincide with the centre of the negative, and the corners 
should all be equidistant, otherwise the lines will be 
distorted. No si)ecial lens is required. When a clear 
view of the sky is obtainable, a Udless box, having an 
opening in the bottom capable of receiving the negative 
and corner pieces to prevent it falling through, may be 
attached to one end of aboard; at the other end is the 
camera. The board at the box end is fastened to the 
window sash with eyes ; the other end is suspended with 
string so that the negative points to the clear sky and 
even illumination is ensured. 

Making Wax Candles.— Wax bandies are made in 
machines each capable of moulding fifty or one 
hundred candles at one time. The machine is simply a 
framework holding a large tray having a number of 
circular holes. Under each of these holes hangs a 
candle mould with the point downwards. The wicks 
are wound upon bobbins below, drawn through the 
points of the moulds, and then stretched tight by fixing 
to a frame above so that they pass up the centres of 
the moulds. Surrounding the moulds is a trough. The 
molten wax is poured into the tray, from which it falls 
into the moulds. Cold water is then run into the trough, 
and the wax immediately solidifies. The excess of wax in 
the tray is removed by a scraper, and the frame carrying 
the wicks is raised so that all the candles are drawn 
out of the ' moulds. The wicks are then cut and the 
process i-epeated. The waxes used are parafiin wax, com- 
posite (paraffin wax with 5 to 15 per cent, stearic acid), 
cerasln, etc. 

Colouring a Malacca Cane.— To colour a malacca 
cane, mix, some spirit aniline dye in thin spirit varnish. 
Bismarck brown yields a rich red ; yellow may be ob- 
tained in various shades, but must be very strong 
in order to gain a good colour, unless the upper surface 
of the cane is removed by the aid of No. 1 glasspaper. 
The cane may be finished with clear spirit varnish, 
though better wearing results would be gained by a thin, 
even coat of best quality coach varnish. 



96 



Cyclopaedia of Mechanics. 



Properties and Use of Plorlc Add. — Picric acid 
Is formed by the action ot nitric acid upon phenol 
(carboiio acid). Picric acid iaapale yeUow crystalline 
substance sometimes used in dyeing, as it yields a flue 
pale yellow upon silk. It is principally used in the 
preparation o£ some of the "high" explosives. It 
does not explode by applying a light or by friction, 
but when a strong detonating cap is exploded in a cart- 
ridge of picric acid, the latter is caused to explode with 
terrific violence. The combinations of picric acid with 
soda and potash are amongst the most powerful ex- 
plosives, but as they sometimes exnlode spontaneously, 
they are rarely used. 

Small Cart for Pony.— A cart suitable for a pony 
from 11 to 12 hands high is shown below. The length 
of the body is 4 ft. at the bottom and 2 ft. 6 in. on the 
seat. The bottom panel sides are lOi in. deep under 
the seat and Tin. at the front. Tlie front board is Sin. 
deep. The top sides are 1ft. deep, and are bent over 
sharp at the top, each being fastened with two halt- 
round irons in addition to being, screwed from outside to 
pieces that the seat slides on, which, with a cross-bar, 
are of birch or oak lin. thick and 3i in. wide before being 



with a bright negative in the printing frame, and expose' 
fully to a good light. Immerse for from fifteen minutes 
to half an hour in a solution containing 23 gr. of 
Rochelle salt and 2,';gr. of borax to loz. of water. 
This gives a black Image. By decreasing the borax to 
9gr. and adding three drops of hydroohlorle acid, a 
sepia picture is obtained. Transfer for ten minutes to 
a 1-per cent, solution of ammonia, then wash for halt 
an hour, and the print is finished. Ferric oxalate may 
be made as follows : Add to 2oz. of ammonia iron alum, 
in a 20 oz. measure, loz. ot strongest liquor ammonia 
with 1 oz. of distilled water. Stir well and allow the 
precipitate to fall. "Wash by decantation till alkalinity 
disappears ■, then add 1 oz. ot crystallised oxalic acid, and ' 
make up to the desired strength with distilled water, 
rerric oxalate purchased ot a chemist should be tested 
by adding to a solution ot it a few drops of a solution of 
potassium ferrioyanide, when, it it has changed to the 
ferrous state, it wUl throw down a dense precipitate of 
Prussian blue. 

Waterproofing Canvas.— To malce "chemical " canvas 
pi-epare two baths, one contS,inlng lib. of yellow soap 
in a gallon of warm water, the other containing lib. 




Small Caxt for Pony. 



dressed. These bent sides can be made ot i-in. walnut 
finished In plain varnish, and give a nice contrast to 
the black japan on the bottom panels; a piece of wide 
wood bead, having a strip of plated bead fastened along 
the centre, going over aU. The bottom of the body 
, is 3 ft. wide, and may be made either quite square or, 
U preferred, spread out each side lin., when 2ft. lOin. 
will be wide enough for the bottom. The bottom 
boards are 1-in. deal. The simplest way ot putting the 
cart together Is to screw a batten along Inside either 
side and nail the boards to these, having a good bar 
of 14-in. ash at back and front, and underneath all 
is nailed a couple of pieces of hoop-iron. The 
elliptic springs are 3 ft. long, with four plates Uin. 
wide. They are fastened to the body with angle-irons 
and blocks lin. deep by 4iln. long. The li-iu. axle 
is cranked Uin. deep. The dash is 22in. long and 
15In. high; wings, 6in. wide, tin. thick, and 2ft. 6in. 
long; wheels, 3ft. 6in. high; stocks, 7in. by 6Hn. 
diameter. Thei-e are twelve If-In, spokes; felloes finish 
1 j in. wide by li in. deep ; tyres, li in. wide. The shafts 
are 4ft. 10 in. long in front ot splinter-bar, and 1ft. Sin. 
wide at tugs, which are 11 in. from points ; they go Inside 
the body, and are fastened in rubber beailngs at the 
front and with a long cross spring at the back. If 
required rather stronger for rougher usage, have the 
stocks 6 In. or 6iin. diameter, and spokes iin. and felloes 
Jin. larger than the measures given. In this case 
the springs might have another plate added with 
advantage. 

Kallitype Process in Photography.— The Eallltype 
process ot printing is the subject of a patent. It con- 
sists of first coating any fairly pure paper with a mixture 
of silver nitrate and ferric oxalate. The ferric oxalate is 
I'educed to the ferrous state by the action of light, and 
thereby reduces the silver In contact with it, thus form- 
ing a visible image, which Is simultaneously developed 
and toned, and afterwards fixed. Dissolve 70 gr. ot ferric 
oxalate in 1 oz. of distilled water, and add 15 gr. ot silver 
nitrate. Brush this solution with a sponge or tuft ot 
cotton wool well and evenly over the surface ot the 
paper, and allow to dry ; then place the paper In contact 



of alum in a gallon of warm water. Pass the canvas 
through the warm soap solution, and then through the 
alum solution. To obtain a very thick coat, put the 
canvas several times alternately through the two baths. 
Old canvas may be treated In the same way as new. 

Advantages of Copper Range Boilers.— The last- 
ing quality ot a copper range boiler as compared with 
an iron one, when used to heat hard water, is not 
worth the extra cost. The incrusted deposit that 
is the usual cause of boilers becoming destroyed in 
hard-water districts will make the copper plate fracture 
nearly as soon as it will the iron. An idea is preva- 
lent that by using a copper boiler the aooumulation 
of deposit from hard water, and subsequent fracture ot 
the boiler, are prevented or avoided, but this supposition 
Is groundless : a copper boiler is at no real advantage in 
heating hard water. In soft-water districts copper is 
largely used because iron will not long withstand the 
active rusting process that the soft water sets up. In such 
places copper boilers, copper cylinders, and lead, copper,' 
or tin-lined pipes have to be used. The thickness ot the 
plate ot copper boilers varies, for copper being such an 
excellent wearing material (when water Is In dose con- 
tact on one side of it), the plate need not be thick, and 
J-in. plate would be ample if It were not that copper is 
soft and cannot withstand heavy water pressure, nor the 
blows that the cook delivers against the boiler front 
with the poker. Therefore the usual thickness is iVli- 
body, with (Vin. or i-in. front-plate. It the boiler is large. 



and the water pressure exceeds, say, 40 ft., then either a 
thicker body-plate must be used, or brass stay-bolts 
must be placed across the body-plates. Brass or copper 



bosses must be brazed around the pipe holes, to allow of 
a sound joint being made ; and. In hard-water districts. 
It is important to remember to order a manhole large 
enough to insert the hand for cleaning. A 3-in. hole and 
a 3-in. plug are usually sent to make the manhole and lid, 
but this is too small. The cost varies with the market 
price of copper, but the boilers are usually some- 
thing under Is. per lb. Copper boilers, before they get 
beyond repair, should have a piece dovetailed in and 
soundly brazed. 



Cyclopsedia of Mechanics. 



97 



Mounting Photographs.— Pill a large hand basin or 
ilish with water, and immerse the photographs in it for 
a few minutes, allowing them to drain slightly alter 
renioval, and then place them with the image down- 
wards on a sheet of glass. Lay over them a lew thick- 
nesses of blotting paper and roll out excess Of moisture. 
Now brush over the top one with some Higgins' photo 
mountant or fresh starch paste, lif^ It carefully by the 
corners and lay in position, cover with fluffless blotting 
paper, and with a squeegee roll gently twice. If the 
photographs are to be mounted iln an album, wet 
mounting may cause cockling, and In such case an 
alcoholic solution of gelatine should be used : Nelson's 
No. 1 gelatine, 1 oz. ; water, 3 oz. : glycerine, 2 dr. ; 
methylated alcohol, 10 dr. Dissolve the gelatine in the 
water, then add the glycerine and alcohol last. In 
this case the position the print is to occupy is marked 
on the leaf ; and, the print having been dried in contact 
with glass, a thin coating of solution is run rapidly round 
the edge of the print or within the line on the leaf with 
a small brush and the print rolled into contact. It is 
always advisable for a beginner to gain skill and ex- 
perience by practising on wasters or spoilt prints. 

Crate for Carrying a Pig. — The accompanying 
drawing is almost sell-explanatory. The size of the 
crate would depend upon the size of the pig, but 
about 4ft. 6in. long by 2ft. 6in. wide and 21t. 6in. 
high will be large enough for any ordinary 
animal. The framing should be of good yellow deal 



When this first coat has dried quite hard, rub it down 
with No. glasspaper ; dust the model and give it another 
coat of the same paint ; repeat this process at least 
six times. Then give it another coat, but, instead of 
smoothing it with glasspaper, rub it down with powdered 
emery and water, using a piece of hair-felt. Repeat this, 
and a beautiful white will be the result. Do not varnish it. 

Air Vessels on Pumps.— The bottle-shaped air 
vessels are used to produce an even, uniform dis- 
charge from the pump, the action of the pump 
plungers being intermittent. Air is stored inside the 
vessel, and the water, after having passed through the 
delivery valve when the vessel is on the delivery pipe, 
compresses the air. When the plunger makes the suction 
stroke, the air cushion acts as a spring and delivers the 
water. A suction air vessel should be used where the 
length of the suction pipe is great in comparison with 
the diameter and tor high-speed pumps. The contents 
of the air vessels vary in different makes from three times 
to ten times the capacity of the pumps. 

Grotesque Target for Shooting Gallery.— The 

illustration shows a front elevation of a novel shoot- 
ing gallery target with the front removed. Make a 
square box, say 2 ft. square, and from 4 in. to 6 in. 
deep i have a circular hole about 9 in. diameter in the 
centre of the box. Out a grotesque head of zinc from 
4in. to6in. in diameter; extend the shoulder'and neck 




Crate for Carrying a Pig. 

Sin. square, and the laths 2Hn. by liin. The latter 
can be either mortised into the framing as shown, or the 
rails can be kept back from the face and the laths nailed 
on. The roof should be of 1-iu. tongued and grooved 
boarding, and the floor should be formed of li-in. boards 
laid with spaces of about lin. between them. One end 
of the crate should be made to open to form a door for 
the entrance and egress of the pig. Two small iron 
wheels, say about 8 in. diameter, can be fixed, one at each 
side of the crate ; a i-in. wheel should also be mounted 
In the middle of each end. The crate would thus have 
four wheels, but would run on the two side ones only ; 
the other wheels would pre vent the crate from ploughing 
into the earth when the pig shifted its position. 

Covering a Pulley with Leather.— A cement made 
as follows may be used with great success, both for 
covering pulleys with leather and on belt joints before 
riveting. The leather wiU tear before coming ofl:, if 
carefully done. Make an extract by digesting 1 part of 
coarsely crushed nut-galls with 8 parts of rainwater, 
let stand for several hours, and filter through, linen. 
Then pour 1 part of cold water over 1 part of best glue, 
let it stand for twenty-four hours, and heat to make a 
concentrated glue solution. To use the above, warm 
the nut-gall extract, and coat the leather with it. Warm 
the pulley, which should be roughened, and coat with 
the glue. Lay the leather on the warm pulley, press 
firmly together, binding it tightly with cord. 

White Coating for Model Boats.— Most makers of 
model boats have found that it is practically impossi- 
ble to give, a model a pure white surface by painting 
it in the ordinary way with zinc or white-lead. 
After- standing a day or two it takes a yellow or may- 
be a dirty white tinge. If the following directions 
are carried out in a careful and cleanly way, a ptire 
white surface which will stand the test of time and sun- 
light will result :— After the model has been thoroughly 
glasspapered down, give it one coat of paint, made by 
mixing ordinary white French polish with flake white 
powder untU it has the consistency of skimmed mUk. 




Grotesque Target for Shooting Gallery. 

downwards a few inches, having a pivot A of wood or iron 
through the neck, the bearing being at each side of the 
box, so that the head will be in the centre of the box. 
Attach a piece of stout wire to the bottom of the neck 
piece, and, so that it swings as a pendulum in a slot 
in the bottom C, fasten a piece of lead B to the bottom. 
A bird or any animal may be made to work the same as 
the head. 

Making Angle Zinc— To make angle zinc to be 
used tor constructing an aquarium, after cutting 
the sheet zinc to the required width, mark it deeply 
with the scriber or cutter along the bending line on 
the underside. Then place the zinc along the flat 
side of a beok-lron or the edge of a hatchet-stake, and, 
keeping the. bending line upon the tool edge, press both 
long edges downwards, commencing at one end and 
working along the zinc until the opposite end is reached ; 
then smooth down to the angle required with a mallet or 
dresser. 

Fickle for Gun-metal Castings.- The percentage of 
water to sulphuric acid to be used as a pickle for 
gun-metal castings depends on the composition of the 
metal. Try by experiment. A pickle for the outer 
skin would be 10 of water to 1 of acid ; leave in a few 
hours to remove sand, and finish by dipping in aquafortis 
and swilling quickly in plenty of water. Dry out in hot 
sawdust ; or dip in hot water and use cold sawdust. In 
the trade, old dilute aquafortis is used as a' pickle for 
castings, which are left in it overnight and dipped in 
strong acid afterwards. 

Recharging Ink Pad of Typewriter.— A suitable 
ink may be made by dissolving 1 part of aniline black 
(soluble in oils) in 6 or 8 parts of oil of cloves by a 
gentle heat ; while still warm, apply It to the pad vsich a 
camel-hair brush. Another ink may be prepared by 
grinding together very carefully 1 part of gas hlack and 
5 parts of oil of cloves ; but to make the latter pro- 
perly, a grinding plant is necessary. If the pad is worn, 
it is useless trying to treat it. 



98 



Cyclopaedia of Mechanics. 



How to Start a Dynamo.— Before stai-ting a dynamo, 
examine it carefully to see that the hruBhes, mbrieatora, 
etc., are in order. The machine may then he run at full 
speed for a short time, with the brushes off, to see that 
the hearings are in order. It should then he stopped 
and the brushes adjusted to their places on the commu- 
tator. The main switch may then be closed and the 
dynamo set rvmning, the speed being increased until 
tlie voltmeter or a pilot lamp shows that the correct 
voltage has been reached. Then, as the load comes on, 
the brushes may be shifted backwards or forwards, as 
may be necessary, for sparkless commiitation. 

Retouching Medium for Fhotograpliic Negatives. 

—The simplest retouching medium is made by dis- 
solTing about half a teaspoonf ul of powdered resin in 1 oz. 
of turpentine. Add the resin a little at a time, shaking 
well. It will probably take about two days to dissolve, 
but it should be shaken occasionally. Apply with the 
bnll of the finger, rubbing well with a circiilar motion 
until it resists. Take the supply from the top of the 
cork and not dii-ect from the bottle. Avoid streakiness 
or the least unevenness. Ketouching medium can also 
he bought ready made of all dealers in photographic 
requisites. 

"Pavodllos" Joint in Flooring.- A sketch of the 
" Pavodilos " rebated joint as used in ftoor boards pre- 
pared for secret nailing is shown by Pig. 1. It is patented, 
and the name is I'egistered as a trade mark by 
the manufacturer of the joint. "Pavodilos" jointed 
flooring and matching Is, however, turned out by other 




Fig. 2 
"Pavodilos" Joint In Flooring. 



firms who work under licence; and some specimens 
are worked as shown by i'ig. 2, which, although the 
second key is lost, may possibly be preferred on account 
of the danger, when nailing down the flooring jointed 
as in Fig. 1, of damapting the feather-edge of the board 
that is being fixed. 

Securing Dowelled Work Togetber.— The holes 
for dowels should be made exactly opposite each other 
in each piece forming the joint. Then the dowel 
should be accurately fitted in. When the work is 
ready for gluing up, the dowels should be glued in one 
part of each joint first, then the other part of the joints, 
dowels, etc., should be glued ; the whole should then be 
quickly cramped up— that is the joints forced up 
close. Frequently it will be round advisable to leave 
the cramps on until the glue has set or become hard. 

Composition of niuntz Metal.— Muntz metal consists 
of 57 parts of copper and 43 of zinc, or 60 of copper and 
40 of zinc, or 66 of copper and 31 of zinc. 

Determining Contents of Circular Tank.— A rule 
for finding the contents, in gallons, of circular tanits 
is as follows : First find the contents in cubic inches and 
multiply by "0036, or in cubic feet and multiply' by 6'23. 
'The cubic capacity of a circular tank In cubic inches 
equals the diameter in inches squared (that is, multi- 
plied by itself) multiplied by ^©l and by the length In 
inches. For the capacity in cubic feet, take all dimen- 
Bions in feet. As an example, the contents of a circular 
tank 4 ft. diameter by 6 ft. high equals 4 x 4, x -7831 
X 5 X 6-2:3 = 391 gal. (roughly). 

Proportioning Rooms for Sound.— Wy bom's "Notes 
for Architects and Draughtsmen" gives the following 
rules tor the proper proportions for a building in order 
that speaking from platform or pulpit may be distinctly 
heard all over the room. For concert rooms, etc., 
height 2, width 3, length 4 or 5. Example:— Free Trade 
Hall, Manchester; height 52 ft., wldtli 78ft., length 
135ft. For lecture rooms, etc., height 2, width 4, length 3. 
jExample :— Theatre of Eoyal Institution; height 30ft., 
■width 60 ft., length 45 ft. The hearers should not be at a 



greater distance from the speaker, for convenient 
hearing, than 50 ft. in front, 30 ft. on each side, and 20 ft. 
behind. No person should be farther than 70 ft. from 
the speaker. The greatest number that can hear a 
speaker conveniently is 2,000, arranged in two tiers. The 
end opposite the orchestra or speaker should be serai, 
circular, or have the angles rounded. The ceiling 
should be elliptioal or coved, and there should be a 
hollow space beneath the floor. 

Concrete for Foundations.- In gauging up concrete, 
bwnt ballast, with or without clean brick rubbish, 
will make fair common lime concrete, but for good 
concrete there should be no burnt ballast, and the brick 
rubbish should be clean and hard. For cement concrete, 
stone ballast and hard bricks, broken to pass a 2Jin. 
ring, would be suitable. One of lime to Ave of the other 
materials, or one of cement to seven of the other 
materials, Is an economical proportion. Burnt ballast, 
like a common place-brick, crumbles on exposure to 
the weather, and In damp foundations will in course 
of time go the same way; even in dry foundations it 
will not bear a heavy load. 

Fitting Windsor Chair as Barber's Chair.— The 

following Is a sketch that shows how to convert a Windsor 
chair into a barber's chair. Make two brackets, as in 
Fig. 1, out of elm or other hard, tough wood, and bore a 
hole through the centre of one, as indicated by the 
dotted circle. Screw the solid one to the seat of the 
chair at the back, and the one with the hole bored 
In to the back of the top piece of the chair. The plain 
sides of the brackets must be so fitted ithat when fixed 
the two mortises are in a straight line with each 
other. Now fit a piece of wood about 3 ft. long into the 




Pittihg Windsor Chair as Barber's Chair. 



mortises in the brackets, so that it will slide easily up 
and down. Fix a cross-piece to the top of this, as shown 
in Fig. 2, and also bore holes up the middle at intervals 
of 1* in. To fix the sliding piece at the height required, 
an iron pin Is used ; this should be connected with the 
top bracket by a short length of chain. The cross-piece 
should be covered and padded. 

Jonval Turbine.— This works by pressure, and may 
be drowned or connected to a suction tube. It is an 
axial or parallel-fiow turbine, the water passing through 
the motor in directions parallel with the central 
shaft. The water enters a fixed wheel, and is guided 
into the movable wheel keyed to the shaft, which 
rotates on a pivot bearing. To regulate the power of the 
turbine, a number of the guide passages are closed by 
a special casting, carrying a segmental rack worked by a 
worm. The efdoleucy of the Jonval turbine increases 
with the load. 

Working Celluloid.— To work thin sheet transparent 
celluloid into different shapes, it is pressed with heat in 
a hydraulic or other press or mould, and allowed to oool 
gradually. A French recipe lor non-iufiammable cellu- 
loid consists in dissolving ordinary celluloid in acetone 
in about the proportion of 25 grammes of celluloid to 250 
grammes of acetone, and dissolving pulverised magnesium 
chloride in alcohol in the proportjion of 150 grammes of 
alcohol to 50 grammes of magesium chloride. Then mix 
the two solutions so as to obtain finally a pasty mass, 
containing, say, 20 grammes of the magnesium chloride 
for each 100 grammes of the celluloid. An uninflammable 
material, similar to celluloid, was invented in 1896 by' 
Cadoret, of Paris, which he claims to be a substitute 
for Indiarubber, celluloid, leather, oilcloth, linoleum, 
mother-of-pearl, tortoise-shell, amber, ivory, etc., and 
which Is capable of being moulded, drawn, or made into 
threads, and in the form of plates, tubes, and cylinders, 
or soft and silky threads resembling silk In appearance, 
and can be dyed in various colours. It has another 
peculiarity— that while the dies or rolls are cold, there if 
no polish on the surface of the rolled sheet Or moulded 
article, but with heat and pressure the polish of the 
mould Is given to the pressed article. This material, to 
which the name of " textiloid " has been given, can be 
made as transparent as glass. 



Cyclopeedia of Mechanics. 



99 



Diminished Twisted Column In setting out and 

working a diminished twisted column for masonry, first 
set out the column to the extreme diamete? of out- 
side of wreath or roll, with the diminish and entasis as 
in an ordinary column. Having decided how many 
times the wreath is to encircle the column, set out the 
spiral to a developed line. If a piece of paper is cut the 
shape of a right-angled triangle, the height of the per- 
pendicular heing equal to the height of the cylinder, 
the hypothenuse (or long side ot the triangle) will 
generate a curve winding round tlie cylinder in the form 
of a spiral. This curve is called the helix, and is the 
developed line of centre of wreath or roll required. In 
order to illustrate this more clearly, take two long 
ribhons of jjaper cut parallel, one piece heing white and 
the other piece black j wind first, say, the white round 
the cylinder, leaving a parallel space just sufficient for 
the black piece, which now wind round the vacant space, 
touching perfectly each of the edges of the white band. 
This being done, let the white band represent the roll 
and the black band the hollow, or vice versa. This 
example applies to a cylindrical shaft whose ends form 
equal parallel circles. In the case ot the tapering 
column the developing ot the spiral line will requii^e 
great nicety in the setting out ; and although the band 
will" not be quite parallel, the principle is the same. The 
shaft is flrst worked as a plain column to the extreme 
or outer diameter. The spiral line is then traced i-oimd 
the shaft, and the hollow worked out. Lastly the roll 
is rounded off, each process being guided by reverses 
or templates. 

Construction of Double-contact Electric Push.— 
The essential parts are shown in the adjoining 
illustration. A push A is connected to a spring B. Under- 




Construction of Double-contact Push. 

neath the push is a smaller spring contact C, and at the 
side opposite B is another contact D. B, C, and D each 
have terminals, not necessarily in the form sketched. 
By these terminals the connections required may be 
made. In the standing position B and D makfe contact, 
but by pressing A the circuit is made byway of B and c. 

Separating Lead from Zinc— The mixture can be 
raised above a red heat, when the zinc will burn away ; or 
it can be granulated, and then placed in acid to dissolve 
the zinc. Or stir into the molten mixture a quantity 
of ground sulphur, which wiU combine with the zinc and 
rise to the surface, and form a crust or cake, which can 
be taken off. 

Taking Apart and Cleaning English Lever 
Watch.— Before attempting to clean a watch, it is 
advisable to become thoroughly acquainted with its 
mechanism. First remove the hands and dial, then 
unscrew the balance cook and take out the balance, 
unpinning the hairspring if necessary, and notice 
how far through the stud it comes, so that it inaj be 
Droperly replaced when putting together again. Then 
.et down the mainspring by lowering the click screw 
under the pillar plate and putting a Hey on the square 
of the barrel arbor. Take out the barrel and bar, also 
the pillar pins, raise the plate gently, and with a pair of 
tweezers remove the lever ; then take off the top plate 
and remove all wheels, etc. Place all the parts, except 
the barrel and fusee, in benzine. Take out and brush 
clean with a soft watch brush and a trace of dry chalk. 
Brush clean the fusee, take off the barrel cover, and oil 
the mainspring. 'Witn a watch peg sharpened to a fine 
point, clean out the pivot holes. 'To put together, 
place all wheels in position on the pUlar plate, but-not 
the lever ; put on the top plate, and then introduce the 
lever between the plates and get it into position ; then 
get the top plate down properly and insert the pillarpins. 



f^ 



Put in the barrel and bar, put on the chain by dropping 
it through the watch' in positiou, and hook the barrel 
hook in the barrel. With a key on the barrel arbor, 
wind it all upon the barrel and place the fusee hook in 
the fusee. Then set up the mainspring half a turn, and 
wind the chain up on tlie fusee, being very careful to 
see that it goes straight. Oil the pivots in the top plate 
and the balance pivot holes. Put in the balance and 
repin the hairspring, being careful to get it in beat. 
To test this, wedge the fourth wheel with tissue paper, 
and when the balance is at rest the ruby pin should be 
in the lever notch and the lever should stand midway 
between the banking pins. See that the hairspi-iug lies 
flat and beats evenly between the curb pins in the regu- 
lator ; also see that it does not touch the balance arms or 
the plate. See that the balance has a little " endshake " 
in its pivot holes. Oil the bottom pivot holes, and put 
a, little oil on the points of the 'scape-wheel teeth. 
Do not oil the other wheel teeth or the ruby pin. Use 
only the best watch oil. 

Girard Turbine. — This is a parallel-flow impulse 
motor, the power being due almost entirely to the 
velocity of the water. The guide blades, in the ver- 
tical form of motor, may be closed by special vertical 
shutters worked by special gear, and the passages 
through the wheel are widened towards the outlet of 
the water. The efBciency ot the Girard turbine may be , 
highest on low powers. A suction tube cannot be used, 
as the 'wheel must be close to the level ot the tall race. 

Power Transmitted by Leather Belts.— In the 
diagram given below, the curve A refers to single 
belts, best oak tanned, curve B to similar light double 



UUU 1 ' ' ' 














/ 1 1 ' / 










I \ • . X\ ■ - ■ 






















1 1 /. \l>' ■ ^\ ; 1 ' 1 ! 1 












1000-—^^ — / 1 Xi^'^— --^ i 1 i - : ' : 1 1 H ^-r-j — -- 












+T^v:f 'Mil ' ■ ■ M 1 i h 




-/^'iiiiiii''-"'''-^— i.ii'iiii 



HORSE POWSR 

Power Transmitted by Leather Belts. 

belts, and the, remaining curve C to heavy double 
belts. Each curve shows the horse-power that may be 
transmitted by a belt for each inch in width. Thus a 
single belt 1 in. wide wiU transmit about 3 hoi,'se-power 
when running at a speed of 2,000 ft. per minute. 
Similarly, at that speed, a ' light double belt will 
transmit rather more than 4'2 horse-power per inch of 
width, while a heavy double belt would transmit about 
5"i horse-power. It will be noticed that the lines curve 
upward at the higher speeds, the decreased power 
thus shown being accounted tor by the centrifugal 
force set up. To keep the belt central with the face of 
the pulley, the latter should be slightly rounded, say 
|ln. or i in. per foot. 

Making Sheraton Easy Chair. — The frames of 
these chairs are made of deal, and the ,legs of hard 
wood such as birch. The inside only of the chair 
is upholstered, the outside being covered with the 
same • material as secured to the frame. The following 
dimensions are suitable :— Total height ot back, i ft. ; 
width of seat from front to back, 2 ft. j width of seat, 2 tt. ; " 
height of legs from floor to bottom ot seat frame, 10 in. 
without castors; height of arms from seat frame, 1ft. 
The back legs should be liin. square; these can be 
bought ready sawn, with the required sweep of 2 in. at 
the bottom. The front legs are made from 2in. square 
stuff. The seat frame should be 2 in. by IJin., raised 
with a stuffing-rail 2 in. high. The back will have three 
cross-rails 2 in. by fin., stump-tenoned into the back 
legs. 'Web the insides of the back and arms, and cover 
with hessian as a foundation for stuffing. Stuff all the 
inside with hessian before putting on the outside cover- 
ing, which is usually a cotton imitation tapestry. 
The edges can be corded or finished vrith brass or copper 
nails. 



100 



Cyclopaedia of Mechanics. 



Sizes of Whltworth Nuts and Bolt-heads. — 

The following table gives the thickness of the bolt- 
heads and the widths of hexagon nuts in the Whitworth 
standard. The third, fifth, and seventh columns are to 
the nearest sixty-fourth of an Inch :— 



Diameter of 
Bolt and 


TMcliness of Head 


Width of Nut 
across Flats 


Width of Nut 
across Corners 


Thicknessof 


in In. 






Nut in In. 










i 


•4375 


t'» 


•9191 


Sjl' 


1-06 


lA 


t 


•4921 


Si 


1-011 


IsV 


1-16 


Wi 


•5468 


ir! 


1-101 


Wi 


1-27 


ir 


f 


•6015 


ii 


1-20U 


lil 


1-38 


•6562 


1-3012 


IH 


1-5 


1 


i 


•7109 


lA 


1-39 


IS 


1-6 


1' 


•7656 


n 


1-4788 


1} 


1-7 


H 


1 


•8203 


f 


1-5745 


m 


1-82 


1^" 


•876 


1-6701 


i» 


1-95 


le 


1 


•9843 


K 


1-8605 


1 J 


2-15 


2^ 


1 


1^0937 


iK 


2-0483 


2,\ 


2-36 


25* 


1 


1^2031 


in 


2-2146 


Ml 


2-55 


2 
2rf 


1 


1-3125 


lA 


2-4134 


2-78 


1 


1-421 


IS 


2-5763 




2-97 


2 


1 


1^5312 


2-7578 


3-18 


3A 


1 


1-6406 


3-0183 


3A 


3-48 


3"- 

34 


2 


1-75 


1^ 


3-1492 


a^n 


3-63 



The odd iV-ln- sizes given above are seldom used. 

Inexpensive Filter for Oil.— To make a cheap filter 
for light machine oil, obtain a large ribbed glass 
funnel about 6 in. diameter ; take a clean sheet of thick 




FlQ. 1 



Inexpensive Oil Filter. 



wnite blotting paper, and cut from it a circle 10 in. dia- 
meter, then fold the paper twice to the shape shown in 
Pig. 1, and openitout like Fig. 2, so that itfltsthe funnel. 
Now place the paper in the funnel and the latter 
into a clean can, and pour the oil into the paper, 
taking care that it does not flow over. The oil will filter 
through slowly, and will he perfectly clear and bright. 
"When the paper becomes.clogged, it must be replaced by 
a new piece. 

Brazing Bandsaws.— Ordinary handsaws may be 
brazed as follows :— Taper the ends of the saw by filing so 
as to form two wedge-shaped ends for about the length of 
three teeth. Lap the ends, and place a small quantity 
of the fiux on them j cut off a narrow piece of the brazing 
metal (about lin. by tin. will do for an inch saw), 
place it hetween the ends of the saw, and cover the joint 
with flux. The saw, being clamped and held in position 
in a suitable holder, is now ready for brazing. Heat to a 
bright red heat a pair of heavy ton^s, free from scale 
between the jaws, and hold them tightly on the saw 
until the brazing metal melts ; then slip off the heavy 
tongs, and grip the braze with a lighter pair that has 
been made black hot. When the joint Is well set, remove 
the tongs and file the braze to uniform thickness. The 
saw is ready for use when the teeth where the joint is 
made have been sharpened and set. For brazing heavy 
bandsaws, a small machine may be used, by which the 
saws are kept in position over the flre by means of a 
hinged clamp having set-screws on each side of the joint. 
The brazing is done with two pairs of tongs. Brass spelter 
and borax as a flux makes very strong joints in band- 
saws of ordinary widths. Equal parts of copper and 
coin-silver, melted well together, rolled out thin and cut 
in strips, is said to make good brazing metal. One ounce 
ie sufficient to make over thirty joints, in bandsaws lin. 
wide. Two ounces of flux will be sufllcieut for loz. of 
brazing metal. 



Strength of Springs for -Vehicles.— The following list 
has been furnished by a leading axle maker :— 

Mail and Collinge axles suitable for a vehicle bearing 
the load shown :— 

Size 1 li li li li n U If 2 in. diameter. 
Weight 5 7 10 12 15 18 22 26 30 cwt. 

Drabble and cart arms suitable for a vehicle bearing 
the load shown :— 

Size li It 2 2i 2J 2} 3 in. diameter. 

Weight 10 15 20 25 30 45 55 cwt. 

Springs.— A comprehensive list cannot be given, as 
there are so many variations In size ; the quality of 
steel also has a great influence. The following are a 
few customary sizes of trap and cart springs, with the 
weights they are supposed to he suitable for :— 



Size of Spring. 




44 in. X IJ in. x 5 in. 
46 in. X l| in. x 5 in. 


6 cwt. 


8 cwt. 


48 in. X 2 In. X 5 in. 


10 cwt. 


48 in. X 2 in. X 6 in. 


12 cwt. 


48 in. X 21n. x 7 in. 


14 cwt. 


48 in. X 2iin. X 7 in. 


17 cwt. , 


48 in. X 2iin. x 8 in. 


20 cwt. 



Ordinary merchant quality springs are made of steel 
of unguaranteed temper, hence the temper is variable, 
often resulting in weak, unsatisfactory springs. Buyers 
of springs should require a guarantee that they are 
made of guaranteed material with a temper, for heavy 
cart and waggon work, of not less than 0-40 per cent, of 
carbon ; for light trap and carriage work not less than 
0-45 per cent. 

Wire Rests In -Wet-plate Photography.-In wet- 
plate photography, the silver wires on which the plate 




Wire Rests in Wet-plate Photography. 

rests are fixed in the carrier, as shown in the accom- 
panying Illustration. This special device is used 
because the drippings from the wet plate exercise a 
destructive influence on the woodwork of the slide, but 
an ordinary slide may be used if blotting paper is placed 
along the bottom to absorb the drippings ; or the slide 
may DC coated with shellac, asphaltum, or paraffin wax. 

Lead of Slide Valve of Steam Engine.— The lead of 
a slide valve Is the amount by which the steam port is 
open when the piston is just going to commence its 
stroke. The supply of steam to the cylinder then 
commences before the stroke, and the moving piston 
is brought to rest against a cushion of steam. The 
amount of lead varies from All- to Ain.. according to 
the type of engine. 

Damp-proof Stiffening Solutions.— For stiffening 
materials that wUl be exposed to damp, a solution 
similar to that used for stiffening hats is suitable. 
This is composed of 5 parts sheUac and 1 part borax, 
with suiflcient water. A useful water-proofing material 
may be made by dissolving shellac In ammonia. 
A good stiffening waterproofing material is boiled 
linseed oil, which stiffens by exposure to. air and is 
very pliable. Another waterproofing substance may 
be applied by passing the materials through a soap batli 
and afterwards through alum solution ; this produces 
an alumina soap in the fibres and stiffens the fabrics. 

Polishing Ebony Walklng-stlote. — To polish an 
ebony walking-stick a jet black, mix Frankfort black 
or black aniline spirit dye with the polish ; the latter 
may be made by dissolving 6 oz. of garnet shellac in 
Ipt. of methylated spirit. Apply with a camel-hair 
brush. Best results are gained if polishing pads made 
of wadding enclosed in fine rag are used. 

Ink for Rubber Stamps.— To make a good rubber 
stamp ink, pulverise 180 gr. of aniline violet and dissolve 
in 2 oz. of boiling distilled water ; add one teaspoonful or 
glycerine and half a teaspoonful of iireacle. 



Cyclopaedia of Mechanics. 



101 



Fern Case Construction.— Fig. 1 shows a section 
through a part of a case for rearing ferns. The 
bottom is of deal, with a polished mahogany edging pr 
rim which forms a base, the bottom being tongued to it 
on each side and fixed. The bottom stands i in. below 
the rim. to receive the tray A. The latter is 2iin. 
deep, with a hole In the centre to convey superfluous 
moisture to the zinc safe B underneath, and is covered 
with a thin layer of broken brick, or other similar 
material, and with 2 in. of mould, in which the ferns are 
planted. The safe slides between the feet C, on which the 
case rests. The zinc tray should be ftrst fitted into the 
bottom and secured with screws, the heads soldered over, 
the channel edging D bent to fit the domical glass at each 
end, and also mitred at the angles to fit the rails on the 
base, composed of the same section material. Well solder 
the angles together, then put screws along the iualde of 
the channel into the base, as shown, and run a little fine 
solder along the edge to fix it to the tray. Then put the 
glass into position by slightly extending the framework 
at the ends, and bring the frame tight to it. Take a 





FnS 



Constructing a Fern Case. 



piece of bell tube the same length as the out to out of 
frame and solder at each end, keeping the joint in the 
tube at the top. A piece of ornamental cresting, slipped 
into this joint and soldered to the tube, will give a good 
finish to the case. Make the doors at each end out of 
angle pieces to fit the frame as shown, and hinge on the 
Side. The glass in these doors must be left short from 
J the top for the admission of aii:, otherwise the plants 
will be stifled. 

Steam Consumption in Engines.— The most eco- 
nomical steam consumptions in simple, compound, 
and triple engines per indicated horse-power hour have 
been found on trials. A simple Corliss engine has used 
ITJlb., and a simple Schmidt engine, with superheated 
steam, 17i lb. Of compound engines, several American, 
French, and' German engines have used more than 121b. 
and less than 141b., while a triple-expansion WlUans 
engine may uss 12} lb., and a similar Sulzer engine less 
than 121b, 

Removable Vestiliule Screen.— The sketch shows how 
a frame may be fixed, without injury to the premises, 
as a tenant's fixture, removable at the expiration of 
the lease. No plugs are allowed to be put into walls, and 
where fixing is required it must be done by means of 
screws— nails are not permissible. Take the exact width 
between walls, and allow 11 in. narrower in the outside 
width of the frame. The skirting projects, say, iin. on 
each side ; the frame must be scribed over this equally 
on each side, as shown. Get four brass angle-plates 0, 



chamfered on face for preference ; let one side into the 
edge of the frame in each case, the other screw on to 
the face of the skirting. This will securely fix the lower 
part; an additional fixing is obtained by screw D into 
floor. The upper part must be secured by means of 
folding wedges B, i in. wide, between the frame and 
plaster. These should be driven tightly home, and 
should be placed as nearly as possible over the jamb at 
the top and at the level of the transom at the side. 
When the frame is firm, drive some fine brads through 
the edge of the frame into the wedges, to keep them from 




Vestibule Screen as Tenant's Fixture. 



moving if the frame ia jarred by the banging of the door 
at any time. The fillets A shown on the edge may now 
be fixed ; they must be scribed over the skirting and to 
the plaster, and fixed to the frame with panel pins. 
These fillets completely hide all fixing with the exception 
of the end of the brass bracket on the skirting, and this 
is not unsightly. The job, it carried out properly, will 
be a good one, and the screen, while equal in stability 
and appearance to a permanent fixture, can be quickly 
and easily removed. 

Resin used in Spirit Varnish.— Shellac dissolved in 
spirit forms the basis of most spirit varnishes ; the 
addition of resin is often advised on the score of cheap- 
ness. It also assists the varnish to fiow level, gives it 
more body, and imparts a brightness not obtainable by 
the use of sheUac alone. As excess of resin yields a var- 
nish easily scratched, benzoin is added to make it 
harder, in addition to increasing its brilliancy. BheUao 
and spirit alone will suit for some purposes as a varnish, 
but win generally need more shellac in than when for 
use as French polish to be applied by means of pads. 



102 



Cyclopaedia of Mechanics. 



Renovating Patent Leather Sboes.— To renovate the 
enamel of patent leather shoes, tree them up tight, and 
with a sharp knife skive off all the ragged parts of the 
enamel. Now rub over the whole with vei-y fine sand- 
paper. This will make the shoes look dull, but they can 
be revived with leather varnish, patent varniiih, ordinary 
blaok cream, Nubian, ebonite, or even a thin coat of 
black polish as used by French polishers. 

Putting Spring Seat to Cushion-seat Couch.— To 

convert a cushion-seat couch into a spring-seat couch, 
take off the couch back ; this will be nailed to the 
body along the bottom and into the head. If the 
bottom is boarded, remove the boards, and put a stuffing 
rail on the front 2 in. high ; this will loave a rebate for 
tacking, banding, etc. If a very soft seat is desired, 
cross-web the bottom with best spring webbing. If 
spring rails are regulred, let five in at equal distances 
apart iii the front and back rails. Ten 8-in. spiral 
springs will be wanted;. secure two to each spring rail 
with wire staples, or, if a webbed bottom, tie fast with 
strong twine through the web. Cover the bottom over 
the springs with coarse canvas, tack on the front side 
securely, and pull down the other till the springs are 
compressed about a quai-ter their length ; then tack the 
other side. Put your arm under the ends, and place the 
springs in an upright position, then stitch fast to the 
cover with needle and twine. Put on a layer of flocks 
about 2 in. thick, cover the top with another piece of 
canvas, and tack fast all round j stitch up the front edge 
to a fine point with four rows of stitches. The couch 
wiU now be ready for outside covering. 

Turning a Crank -shaft.— The adjoining sketches 
show one method of turning the crank-pin of a small 
crank-shaft of an engine. Pig, 1 being a front eleva- 



the surface is rubbed with a very hard brush of couch- 
grass, and then with the lightest and linest-qiiality 
charcoal, the flat portions with stick or cake charcoal, 
the carved or incised portions with powder, using 
linseed and turpentine to keep the surface cool and 
moist. This process yields best results when employed 
on woods of a hard, close grain. 

How to Make Collodion.— Take 1 oz. of pyroxylin or 
collodion cotton, 36 oz. of ether, and 12 oz. of alcohol of 
90 per cent, strength ; place in a dr.v, stoppered bottle, 
and shake from time to time till dissolved. The best 
liquid for diluting the collodion is a mixture of ether 
and alcohol In the above proportions. 

Drying a Mop.— As a means of twisting a mop for 
the purposes of drying, other than by the ordinary 
method of using one hand and a wrist, a hole is some- 
times bored through the handle about 15 in. from 
the upper end, and through this is rove a short 
line, say 30 in., a knot tied close to the hole on either 
side keeping the line in place. By starting the mop 
twisting in a vertical position and pulling both ends 
of the line and releasing them together, the mop is 
rotated quickly in alternate directions. 

Red Filling for Letters on Engraved Door-plate. 

— When fllllng an engraved door-plate with wax, 
the utmost cleanliness must be observed, as any 
foreign matter rises to the surface, and the wax should 
be rubbed down tUl a clean and brilliant colour is 
established. The best vermilion wax should be ob- 
tained, and It should then be powdered. - To do this, 
break the wax into convenient pieces, and place between 
two clean pieces of brass or iron plate ; wi-ap the whole 
in several thicknesses of brown paper, tie with twine. 




Turning a Crank-shaft for Eng^ine. 



tlon and Pig. 2 a side view. Iron slabs, lettered A, 
are fastened, one at each turned end of the shaft 
B, by set-screws C. The slab is centred at E, so 
that D in Figs. 1 and 2 represents the throw of the 
crank. Sometimes the hole in the slab is larger than 
the turned end of the shaft ; the hole is then packed so 
that the distance D between the centres can be adjusted. 
To stiffen the system, long bolts at F are Inti'Oduced, 
being jambed tight by nuts at the ends. The slabs are 
often to the shapes shown by the dotted. lines in Pig. 2. 
The centres of the slabs and of the crank-pin must be in 
line, the positions being set by the aid of vee-blocks, 
plumb-bob, and scribing block. 

Proportions of Square Nuts and Bolts.— The fol- 
lowing are the usual proportions of square nuts and 
bolt-heads :— The width across the flats of black nuts may 
be one and a half times the diameter of the bolt, plus 
from '18 in. to "44 in. ; or of bright nuts, one and a half 
times the diameter.'.plus from ■06 in. to 'ISin. Across the 
angles, rough nuts may measure 2'12 times the diameter, 
plus from ■& in. to '6 in. ; and bright nuts, 2'12 times the 
diameter, plus from ■08 m. to '25 in. The height of the 
bolt-head may be from two-thirds of the diameter of the 
bolt to equal to this diameter. 

Dull Black Finish for Furniture.— To make a black 
stain that will give a dull finish, as seen on Chippendale 
furniture, it is usual first to stain the wood with 
extract of logVood and copperas, followed by solutions 
of acetate or siilphate of iron. This, in turn, is French- 
polished, an intense black being obtained by adding blaok 
aniline spirit dye to the polish. ■ When perfectly hard, 
this is dulled by well brushing with finest-grade emery 
or pumice powder. Staining alone is rarely sufficient for 
any but the very cheapest class of work. The following 
is the French method of obtaining a dull finish on high- 
class goods : The articles are first coated with camphor 
water, and almost immediatel.y afterwards with a coat 
of sulphate of iron and nutgalls. When quite dry. 



and hammer the package well. This will make the wax 
quite small enough. Another plan of filling the lines is 
to heat the plate, and rub in the wax from the slab or 
stick i another is to grind up the powdered wax with gold 
size, set in with a palette knife, and put aside to harden. 
Clean off with alcohol. Or dissolve wax in pure alcohol 
to a creamy mixture, so that It will pour freely and fill 
the letters ; leave to set hard, then clean up with spirit. 

Hardness of Water. — The hardness of water de- 
pends to a very large extent upon fhe nature of 
the rock through which it percolates, and the extent 
to which it penetrates. Deep well water obtained 
from a shaft sunk to a great depth into water- 
bearing strata is usu.ally more or less hard. Water 
issuing from springs may be either soft or hard; 
from granite and the older rocks the water is soft, 
because it penetrates but little; but in the newer 
formations, especially magneslan limestone, oolite, lias, 
chalk, etc., the spring waters are very hard. Water 
from the surface flowing over pure clay or gravel will 
be, as a rule, soft, because there Is little soluble matter 
contained therein ; but from a shell gravel the water 
will be hard. Water collected in shallow wells is often 
very hard, the water percolating readily through the 
soil and subsoil, and dissolving out the salts contained 
therein. The salts not precipitated by boiling are, 
removed every time the kettle is emptied j the scale will 
contain principally the carbonates. In a boiler the 
case is different, as the concentration of the water by 
evaporation causes the precipitation of both carbonates 
and sulphates ; but an analysis of the water is bette^ 
because there may be present chlorides of calcium and 
magnesium, which also render the water hard, and 
may cause trouble in other ways. These salts are ex- 
tremely soluble In water, and would not precipitate how- 
ever long the water was boiled. The deposit inside a 
kettle would be white if only lime and magnesia were 
present ; but if Iron were also present, the deposit would 
ue yellowish or cream-coloured. 



Cyclopaedia of Mechanics. 



103 



Soldering a Silver Watch Case. - Ordinary 
easy running sUrer solder, which melts at a lower 
heat than silver, will do. Btit to make sure, shred 
the solder into very thin strips, and apply plenty of 
borax to them as well as to the joint to be united. Use 
the blowpipe gently at first so as to bake the borax, then 
heat the case all over almost to the melting point of 
solder, and direct the flame to the part to be soldered 
until the solder runs and glistens. Cease blowing 
instantly, and plunge the case into a solution of 
sulphuric acid 1 part and water 10 parts, to whiten it ; 
then wash In hot water and dry in sawdust. Be careful 
to remove all steel springs before soldering a case. 

Size of CorUss Valves for Steam Engines.— The 
diameter of Corliss valves u?ed for the admission of 
steam to engine cylinders when the diameters of the 
cylinders are known may equal one-eighth the diameter 
of the steam cylinder plus 2 in., while the diameter of 
similar exhaust valves may equal one-sixth the diameter 
of the cylinder plus 2 in. Thus, for a cylinder 24 in. 

diameter, the steam valve should be 



2i 



+ 2 = Sin. 



diametei-, and the exhaust valve -g- + 2 =6.in. diameter. 
Dressing Up Spokes of Carriage Wheels. — An 

easily made apparatus that will hold the spokes of 
wheels whUst drefjsing them up Is illustrated by Kg. 1, 
which is a side view snowing a spoke in position. The 
bottom raU A is li in. deep by li in. thick, shouldered 
in at B to 1 in. thick. On this part the block 
works along by the mortise shown in Pig. 2, being 
kept in position by the wedge at the back D (Mg. 1). 
To this block is fixed an iron plate (see Pig. 3), 



Having melted a sufUcient quantity of tin in the bath, 
pass the copper sheet through it, and as it is withdrawn, 
quickly wipe the superfluous tin from each side with a 
pad of tow. The surface of the cooper should be first 
prepared as described above. 

Green Stain for Wood.— A clear dark green stain 
may be made by mixing aniline dyes as sold at most 
druggists' with plenty of hot vinegar. Green and blue 
yield a useful tone. Or apply hot 2oz. of verdigi-is, 
4oz. of China blue, and Ipt. of vinegar; several 
coats will be required. These water stains have a 
tendency to raise the grain. The subsequent rubbing 
down with glasspaper will give the white flecks often 
seen on frames. If this is objected to, colour must be 
used m the polish or varnish. Another simple plan 
IS to use emerald and bronze green mixed in hot beer. 

Making Photographic Prints by Gas and Dull 
Light.— Any gelatino-chloride paper may be slightly 
printed and afterwards developed. The great drawback 
to the process is the liability of obtaining degraded high 
lights with a consequent flattening and.-foggihg of the 
image ; because if the faint image from a brief exposure 
under a negative can be developed into a dark print, any 
chance exposure of the paper to daylight will show by fog 
and degradation. If the paper has been properly protected 
from extraneous light and is otherwise suitable, develop- 
ment has a tendency to intensify the contrasts, therefore 
a little fog is sometimes an advantage unless allowance 
has been made in the negative. Eastmans', Paget, and 
Otto gelatino-chloride paper can be recommended for 
this process. Print a faint Image in diffused light- 
that, is, expose for about five minutes to daylight or one 
hour at 6 in. from an incandescent gaslight. Make up 




Apparatus for Holding Spokes of Wheels. 



the lower part being IHn. wide by }in. thick, the pro- 
jecting centre-point being Jin. round, welded into it. 
A pillar li in. square is mortised on the front end, being 
firmly fixed by a corner plate, as Pig. i: This is made 
with a boss at the top to the full width of plate, H in., 
through which the i-in. screw E is fitted. This has a 
handle fitted at the end, and when in use the frame is 
held in the vice, or may be cramped to the bench, and 
the block is slid along to about the length of the spoke. 
The latter is placed between the two centre-points, a 
turn or two of the screw holding the spoke firm, whilst it 
can also he turned round In any position for working. 

Cleaning and Relacquering Brass.— To clean and 
relacquer brass fittings, take all the parts to pieces 
and place them in a boiling solution of carbonate of 
soda or potash, lib. to a gallon of water. To remove 
the old lacquer, swill in clean water. Then dip in 
commercial aquafortis quickly several times till of a 
golden colour, swill each time in clean water, and add 
a pinch of cream of tartar to the last swilling. Dry 
out in hot sawdust. Burnish the bright parts with a 
steel burnisher, using a little oxgall to lubricate. Dry 
out in sawdust as before. Heat on a hot plate, and 
lacquer with a camel-hair brush. 

Tinning Sheet Copper.— If to be tinned on one side 
only, first smear with salt and water the opposite side ; 
then, with a pad of tow, wash the other side with 
klUed spirits (chloride of zinc) , and also sprinkle a little 
powdered sal-ammoniac over the surface. Place the 
sheet over the fire, and when hot enough, rub the 
end of a strip of tin on it until a small portion 
of the tin melts ; then, with a pad of tow or wadding, on 
which some powdered sal-ammoniac has been sprinkled, 
rub the molten tin over the hot surface, and continue 
this operation until the whole surface is covered. If the 
copper is to be tinnedon both sides, an iron bath of semi- 
circular section, built up over a firegrate, should be used. 



the following solutions :— Wo. 1. Hydroquinone 25 ^., 
metol 10 gr., sulphite of soda 25 gr., potassium bromide 
50 gr., ammonium bromide 100 gr. , water 8 oz. No. 2. 
Sodium hydrate 15 gr., water 2 oz. No. 3. Tannic acid 
8 gr., water 1 oz. Take thirty-two parts of No. 1, eight 
parts of No. 2, and one part of No. 3. Immerse the print 
without washing. It rapidly bleaches to a light yellow, 
then slowly increases in density. When nearly dark 
enough, remove the print and place it in a 1 in 60 solution 
of acetic acid, and thoroughly wash for ten minutes. 
Q-reat care must be taken to wash out all the acid, or 
uneven tones will result. The ni'int may then be toned 
in the ordiiiar.y sulpho-cyanide bath and fixed as usual. 
Avoid handling the paper or stains will result. Another 
method by which prints of a fairly s.atisfactory colour 
may be obtained without toning consists of pouring over 
the dry print a solution of pyro 1 gr., bichromate of 
potash solution (1 gr. in 2 oz.) 10 minims, water 1 oz. j a 
print of a sepia tone results. But it is difficult to avoid 
degraded high lights ; it is, in fact, practically impossible 
if a larger proportion of bichromate solution than that 
given above is used. An acid fixing bath has been 
recommended. 

Cleaning Buff Leather Gaiters.- To clean gaiters 
made of sun tanned sheepskin, with the flesh side 
outside, wash them thoroughly and scrub out all the 
dirt, when quite dry, scrape them all over very 
lightly, paying special attention to the parts that were 
dirtiest, with a dull knife, a buff knife, or the edge of 
a blunt shoemaker's knife; if the knife is too sharp 
the leather will be ycorn away. When the gaiters are 
rough all over, apply some Pi-opert's brown ball, or a 
mixture of brown ochre and chalk mixed to the shade 
required, and rub in well with fine sandpaper, then with 
a piece of old cloth. If the gaiters are then brushed out 
lightly with a soft brush, they will have the appearance 
of new goods. 



104 



Cyclopaedia of Mechanics. 



Secret or Invisible Inks. — The ueual invisible or 
sympathetic inks are made from cobalt nitrate or 
chloride, -which in the hydrated condition (that is, 
containing water) are a pale pink, but become deep 
green by loss oJ water on heating. Writing upon 
paper with these inks is invisible at the ordinary 
temperature, but by warming the paper the marks 
appear very distinct, but fade away again after a short 
time. In hot climates the writing would not be invisible. 
Invisible writing may be done with a solution of tannic 
acid, and developed at any time by soaking in a dilute 
solution of ferric chloride. A true ink is then formed. 
Another method is to write with a solution of boiled 
starch, and develop the writing by damping the paper 
and holding it for a tew minutes over a bottle containing 
iodine ; the blue iodide of starch is then formed, and 
the writing becomes quite distinct for a time. It fades 
away again as the paper dries, but may be developed in 
the same manner several times. Another process is 
to write with a solution of lead acetate, and develop 
by moistening the paper and holding it over a bottle 
containing sulphuretted hydrogen ; the writing then be- 
comes permanently black, sulphide of lead being formed. 

How to Put a Bristle on a Waxed Thread.— To put a 

bi'istle on a waxed thread, as used in shoemaking. D shows 
the bristle split, and the end of the taper of the thread in 
the cratch of it at E. Hold this point between the thumb 
and finger of the left hand, so that it does not pull out 
at the bottom P while the two are being twisted together 
with the thumb«and finger of the right hand. When 
twisted, still hold them flrmly at E, and put the bottom 




How to Put a Bristle on a Waxed Thread. 



P between the little finger and the next finger. With 
the right hand twist the other portion of the bristle- 
that is, the top F. Then put the two P's together, hold 
them with the right hand and let go with the left, and 
D and E will twist of their own accord. Then fasten the 
ends at F so that they cannot untwist, as in the adjoining 
sketch. Take G as the thread or waxed end, and through 
this make a hole between F F and E, but very near to F F ; 
then take D and pass it through this hole. By pulling D, 
E will also pass through the hole— in fact, all the bristle 
except the two ends F F ; that portion of the thread will 
also pass through that has been twisted in with the 
bristle. 

Sticking Artists' Canvas to Millboard. — Having 

rubbed the back of the canvas with coarse glass- 
paper, coat the material with some strong glue, rub 
down thoroughly, and press until dry. Failure often 
occurs through not properly removing the air from 
between the picture ana the mUlboard. The correct 
method is to place a square of thick paper ovfer the face 
of the painting and then expel the air by rubbing, with 
closed fist, over the whole surface, commencing from the 
middle and rubbing towards the outside edges. If air 
gathers under the middle, and it cannot be forced out 
round the edges on account of the glue having set, prick 
the blister with a fine needle, and, having let the air 
escape, rub down well and put a weight on the spot for 
an hour or two. 

Photographic Lens for Portraits and Enlarging. 

—Any lens may be used for enlarging quarter-plate 
pictures to about 12 in. by 10 in. Theoretically, the best 
lens to use for the purpose is the one that has been 
employed t.o take the picture. Practically, the best 
lens is a portrait or rectilinear lens having a flat 
field and a large aperture. The focus should not be 
long, or the camera will require great extension. If a 
S-ln. locus ijortrait lens is used, the camera must be 
extended 21 in. and the lens be placed Sin. from the 
small negative. It is only necessary that the lens 
should sharply cover the small negative. Only quarterr 
plate portraits could be taken with a 6-in. lens. In 
some oases it may be best to fit the enlarging 
samera with a 6-in. rectilinear lens by a good maker 
(such as Boss, Dallmeyer, or Taylor), working at /"/O. 
This could be used as it stood for ordinary work and 
snlarging ; whilst an occasional half-plate portrait could 
ilso be taken by using the front combination only, 



provided the extension of the camera is sufficient. It not, 
a conical front could be made to accommodate It. Every 
lens is supplied with a fiange, which only needs screwing 
to the opening in the camera front. As daylight en- 
largements are best, It Is unnecessary to have a camera 
for enlarging. Place the ftnall negative in a carrier in 
the dark slide with both shutters drawn out, insert the 
slide in the camera, and place it close against the 
window frame, with the lens, covered with a cap of ruby 
glass, pointing into the room. The who^e of the window, 
except a small opening to admit light to the slide, must 
be blocked out and the room rendered thoroughly dark. 
Outside the window must be a white reflector, at least 
four times the size of the negative, flxed at an angle of 
45° with the negative, and receiving light from the sky. 
On placing a sheet of white paper on an upright easel 
and moving gradually from the lens, a position will be 
found (viz. 24 in.) where a sharp enlarged image of the 
small negative is shown on the paper. It is merely 
necessary then to pin a sheet of bromide paper on the 
easel and expose. Daylight exposures are constantly 
varying, and call for some experience, but better grada- 
tion is obtained. 

Fitting Swing Curtain Rails to Iron Bedstead.— 

To fasten rails on the two posts of a half tester iron 
bedstead to carry curtains so that they will swing, 
Fig. 1 shows the arrangement as fl^ed on the pillar 
of bedstead. An iron bracket of wrought flat iron fin. 
by i in. should be made as shown in Pig. 1, the upper 




FIG. 4 

file, f Fia 2 
Fitting Swing Curtain Rails to Iron Bedstead. 



part swelled out and drilled so as to fit over the top of 
pillar on the screw. The brass knob screwed down on it, 
with a washer between, will keep it in place. Pig. 2 
shows the bottom fixing. This is a solid forging drilled 
through the centre to take the pin of the bracket, and 
with a clip for the pole fastened to it with a tightening 
screw. The bracket (Fig. 1) is turned up at the end, 
swelled out and drilled lor a brass tuning to pass 
through ; a small eye similarly made is flxed at the 
back end of the bracket (see Pig. 3). The brass rod 
should have eyes flxed into it about 4 in. apart, as shown 
in Fig. 4. To these eyes the curtains hang from brass 
hooks. The brass knob at the under side of the solid 
bracket rest will keep the bracket tight In its position. 

Distance of Stop from Lens in Camera.— There 
is no arbitrary rule for finding the distance of the 
stop from the lens. It is best discovered by experi- 
ment; the point chosen is where the maximum of 
sharpness is given with a minimum of distortion. If 
distortion is of little consequence, the stop may be 
brought forward until Its circle of illumination just 
covers the plate and no more. The experiment may be 
made in the following manner : — Moi^nt the lens square 
in a tube and then choose another tube, 2in. long, sliding 
into the first easily. (The second or inner tube may he 
made by rolling and pasting paper round a rod built up 
to the right size with paper.) At the end of the inner 
tube, which must be cut straight and true, fix a black 
card having cut In it an opening about one-third the 
diameter of the lens or about one-sixteenth the focus. 
This, hole represents the stop, and by sliding one tube 
withm the other the distance between the stop and the 
lens may be adjusted. Place the camera parallel with a 
number ot straight, clear lines drawn on paper about 
6 in. apart and focus them without the Inner tube till 
they are about 1 in. apart. None ot the lines will be 
really sharp. Insert the inner tube and push the stop 
close against the lens and the definition in the centre 
will at once be improved, but the definition at the 
margins will be as bad as ever. Now slowly withdraw 
the stop and the definition will be seen to'fepread towards 
the margins of the screen. As this is done, however, 
another evil Is Introduced ; the lines at the margins of 
the paper are bent inwards at the ends and outwards in 
the centre. This bending of the lines is known a» 
distortion, and is the result of using a stop. 



Cyclopaedia of Mechanics. 



105 



staining Wood in Imitation of Mahogany. — If 

tho article is unpolislied, it may be stained with 
one pelinywortli of burnt sienna ground in water. 
Mix with stale beer, and brush well over, wiping oft the 
surplus with rag; two coats may be given. When quite 
dry, rub smooth and coat with several applications 
of spirit varnish. The colour may be enriched by the 
addition of a pennyworth of Bismarck brown to 1 pt. 
of varnish applied with a camel-hair brush. 

How to Make a Cheap Writing Tablfe.— The accom- 
panying illustrations show how to make a small wi-iting 
table. The timber used may be common deal, in boards 
44 in. wide and I in. thick : 66 It. will be sufadent. Saw 
seven lengths for the back, 3 ft. 6 in. long, and twelve 
lengths, six for etich side, 2 ft. long. The sides and 
back may now be either nailed or dovetailed together. 
Dovetailing is best, but it Is the more difficult to do. 
If nailing is resorted to, four uprights should be ob- 
tained, IJin. by IJin. by 2ft. liln., and one placed ia 
each corner, so that the boards may be nailed to them. 
"When this has been done, fix the board in front (D, Fig. 1) . 
and then naU ledges, level with the bottom of this board. 



The following has been given as best for soft stones :— 
Take, say, Jib. of putty powder, put it in a jar, cover it 
with nitric acid, and place It in the open air, as the 
fumes are noxious; let it stand for a day, then pour 
off acid and water repeatedly until the water ceases 
to be acid. Polish with the residue. 

Curing Rabbit Skins.— To cure rabbit skins, mix 
bran and three or four times (by measure) as much 
boiling water, and add lib. of alum and ilb. of salt 
to every gallon of water. Stir to dissolve the salts, and 
then cover with a cloth until about new milk warm. 
Place the skins in this, and leave for about twenty-four 
hours; then dry them in the shade, stretching and 
rubbing them well. Stir lip the mixture, and replace the 
skins for twenty-four hours; then dry again, repeating 
the stretching and rubbing. For large skins, the 
rubbing Is supplemented by scraping the flesh side with 
a knife to loosen the fibres. Many now make a mixture 
of oatmeal and hot water, and before this is c[uite cold 
Immerse the skins in it for twenty-four hours, and then 
dry and hand rub as before. If the rubbing has been 
thorough, the skins should be as soft as chamois leather. 




Fig. 2^ 



How to Maie a Cheap Writing Table. 



each side and along the back to support the bottom of 
the desk. The bottom may then be put on, but the wood 
for this need be only fin. thick (an old egg case will do). 
Then the sloping pieces (Pig. 2)should be cut; these 
should be cut out of one piece. When these have been 
fixed on to the back and sides, the lid ^should be got 
ready; it should measure 2ft. 7Jin. by 1ft. 7iin., so 
that it wUl leave Jin. projection each side and ^in. in 
front. Put the catch of the look on the lid, and fasten 
the lid with hinges to the 5-in. board, then secure it to 
the sides and back. The supports for the shelf C (Pig. 1) 
should be cut as shown. When the shelf has been cut to 
the reauired length, 2 ft. 6iin., it should be let into the 
shaped sides iin., and nailed. This may now be fixed on 
to the top of the desk as shown in Pig. 1, and as there is 
i-in. projection at each end, the nails or screws should 
be driven upward. The top part of the shelf can be used 
for books, etc., and underneath pigeon-holes can be 
made, If desirable. Now fit in the lock, cut out the key- 
hole, fill up all joints, etc., with putty, and rub all over 
the table with glasspaper, and it is ready for staining. 

Self-polishing Blacking.— To make blacking that 
requires no polishing, take i oz. of treacle, i oz. of lamp- 
black, a tablespoonf 111 of yeast, two eggs, ateaspoonful 
of olive oil, and a teaspoonful of oil of turpentine ; mix 
well, and apply with a sponge. 

Polishing Stalactites.— The principal thing in poUsh. 
iug stalactites and small stones after they are cut is to 
grade the hardness of the polishing material with the 
stone to be polished. For cutting a surface level, use 
various grades of emery on lead laps, with a separate lap 
for each gi'ade of emery. See that all scratches are re- 
moved. Por the polishing, on hard wood that wiU not 
warp glue a piece of buff leather. On this place a little 
putty powder, which, like the emery, must be used wet. 



Rule for Velocity of Steam.— It has been found 
that the discharge of steam through an opening into 
a pressure less than three-fifths the initial is about 
900 ft. per second. The following rule has been given 
to determine the velocity in feet per second when 
steam flows into a vacuum:— To the Fahrenheit tem- 
perature of the steam add 460, and multiply the square 
root of the sum by 60. The area of pipes for steam 
engines should be arranged so that the velocity of the 
steam does not exceed 130 ft. per second ; a lower 
velocity is better. 

Stereoscopic Photography. — Por most subjects, 
except Instantaneous stereoscopic work, an ordinary 
quarter-plate camera, with one lens only, may he used 
ft provision is made for shifting the camera or the 
lens from side to side for a distance of from 2iin. to 
2}in. ; or if the object itself can be moved the same 
relative distance the camera may remain stationary ; or 
achromatic lenses, paired lor stereoscopic work, could be 
fitted to a half -plate camera. As to plates, in a half -plate 
camera double quarter-plates (6i in. by Ijin.) are often 
preferred. There should be a partition between the 
lenses, and this may easily be made in a square-bellows 
camera by pleating some flexible black material over two 
slips of elastic and fastening it to hooks in the camera 
front and in the back frame. 

• Distinguishing Worsted from Cotton Cloth.- The 
best way to distinguish a cotton cloth from a worsted 
cloth is to unravel the edge, and if of cotton it wUl 
have a wiry appearance ; worsted is soft and woolly. 
But if there is any doubt, hold the threads over a 
lighted lamp beyond the flame ; if of worsted, they will 
shrivel up and burn into a black cinder ; if of cotton, 
they wUl remain- stiff till they get red hot, when they 
will burn into a white ash. 



106 



Cyclopaedia of Mechanics. 



Dead Black for Interior of Camera.— To make a 
duU black stain for the interioi' of a camera , mix powdered 
lampblack aud French polish, using of the latter 
only just enough to malie the black adhere. Too 
much will produce a polished appearance. Another 
recipe is : Aniline black, lllO gr. ; gum shellac, 200 gr. ; 
methylated spirit, .5c)Z. Dissolve thoroughly, and apply 
■with a soft brush quickly. Negative varnish and 
powdered lampblack may also be used. 

Difference between Linen, Cotton, Wool, and Silk.— 

To distinguish the ditfereuce between linen, cotton, wool, 
and silk, examine tlie fibres under the microscope with 
a moderately low power. It will be found that the linen 
or flax ilbres consist of transparent tubes, sometimes 
marked with lines and having very small central canals 
(see A In the illustration). The cotton fibres consist of 
straight or twisted flattened tubes with very lai'ge cen- 
tral canals and quite transparent (see B). The wool 
fibres are very variable, but consist of a number of plates 
or scales built up to form a tube, and the inner tube is 
usually more or less coloured in the natural wool (see C) . 
The silk fibre is usually very small and perfectly smooth 
(see D). The action of chemical agents upon the fibres 
depends upon their composition. Flax and cotton are 
nearly pure cellulose. By the action of moderately 
strong acids, the fibre is somewhat attacked, and the 




C D 

Magnified Fibres of Linen, Cotton, Wool, and Silk. 

result is a parchment-like product: by long-continued 
action of strong sulphuric acid, cellulose is converted 
into dextrine, and by dilution with water and boiling it 
finally becomes glucose (a kind of sugar). Strong nitric 
acid converts cotton into nitro-cellulose or gun-cotton. 
"Weak alkalies do not aft'ect cotton or ilax ; strong alkalies 
toughen the fibre and shrinkit,formingmercerised cotton. 
Wool flbi-e has a composition similar to skin, horns, and 
feathers, and is composed of nitrogenous material Called 
keratin, but contains sulphur also. Dilute acids do not 
affect wool ; strong nitric acid and other acids destroy 
it, the former first rendering it yellow. Alkalies render 
wool very tender ; strong alkalies used hot dissolve wool 
completely. Silkeontainsfibroin, gelatine, wax, albumin, 
etc. Concentrated acids destroy silk, but dilute acids do 
not affect it much ; simply boiling with water removes 
the gelatine or sericin, which amounts to about 20 per 
cent. Weak alkalies impair the silk, and strong alkalies 
easily dissolve the silk entirely. 

Drilling Holes in Glass.- To cut a 1-in. hole In a 
glass plate a copper tube may be used for drilling. Use 
a tube about J in. diameter with the end spread to 1 in. 
diameter. Emery powder should be fed inside the tube 
to form the cutting material and turpentine used to 
dissipate the heat. The tube must, of course, be pressed 
on the glass and rotated. 

Flattening Buckled Copper. — To flatten copper 
that is buckled, hammer the surface with a light 
planishing hammer on a bright tinman's anvil, com- 
mencing at the end and going backwards and 
forwards across the metal with a series of regular blows, 
until the entire surface has been covered. Any hollow 



places along the centre of the strip must be drawn dowm 
flat by hammering from the edge of the hollow out to the 
edge of the strip. Should the strip be wavy or loose 
along the edge, hammer along just inside the edge and 
work back towards the centre of the strip until the edge 
is drawn flat. 

Private Altar.— For a small private altar which can 
be closed when not in use the accompanying figure is 
suggested. The dimensions are as follows : Length, 21in.i 
projection from wall, 20 in . ! height of altar, 21 in. ; and 
height of reredos above altar, 18 in. The ends A A are of 
inch board shaped as shown, the back length in each 
running up to the top of the reredos, as at B. The front 
is chiefly formed of a stout piece of 9-in. board C, pierced 
with a medallion of tracery, which is let into the edges 
of the end pieces. The spandrels below (D D) are separate 
pieces fixed to this board. A similar board, but plain, is 
at the back. The front of the super-altar E Is ornamented 
with sunken medallions. This rises about i in. above the 
altar top F, and might have a projection of .5in. or6in. 
The altar top is made to overhang at fi-ont and ends, and 
a bold moulding G, mitred at the corners, runs beneath 
it. The reredos has a piece H running along its top of 
the same width as its ends. Half-inch boarding will do. 




Private Altax 

for its back, and in order to show up the cross, etc., the 
back might be lined with velvet, the Gothic arcade I 
being sawn out of thin board, worked up, and fixed upon 
the lining. A piece of thin board K, covered with 
similar velvet, should be fixed along the top of the 
super-altar above its true top, and will serve for the 
doors to fold against. The doors L L are hlflged to the 
stout end pieces. On their inner sides the panel of eachi 
might be gilded In diaper and painted with the gold as a 
background -, or it might be lined with velvet, on which 
a sacred' monogram or emblem in brass could be fixed. 
The outer side of one of the doors is shown with 
its panel filled with tracery sawn from thin board, 
worked up with chisel and gouge, and fixed upon the 
wood. 

Iiiquid used for Gold Paint.— In the manufaoturfr 
of gold paint pale copal varnish, thinned with turpentine, 
is often used. Some gold paints are made with a white 
spirit varnish i others are mixed with a medium prepared 
by dissolving collodion cotton in amyl acetate and 
diluting with petroleum ether. When the bronze powder 
has to be mixed with the medium, pale copal varnish, 
thinned with turpentine, is very often employed. 

Cements for Oil Lubricators. — There are two 
suitable cements that will withstand oil and heat. The 
first is made by separating the white from the yolk of an 
eg^, and mixing the former to a stiff paste with powdered 
quicklime. The second cement is made by boiling 
together 6 parts of water, 1 part of caustic soda, and 
3 parts of resin. When the resin is dissolved, the liquid 
is mixed with half its weight of plaster-of-Paris, and at 
once used, as both cements set hard in a very short tune. 



Cyclopaedia of Mechanics. 



]07 



Making Cart Grease.— The materials employed are 
resin oils, resin, heavy petroleum, animal greases, soda, 
lime, etc. The following may he taken as examples :— 
(a) Petroleum residue 40 gal., resin 60 lb., animal grease 
501b., caustic soda lye 2igal., salt 5 lb., dissolved in a 
little water. The oils are heated together, and the soda 
lye and salt gradually stirred In, when partial saponifloa- 
tion takes place. (!>) Eesin oil 100 lb., and slaked lime 
90 lb. ; heat together, and stir thoroughly until a homo- 
geneous mass is formed, (c) Heat together 1 lb. of palm 
oil, lib. ot palm oil soap, 551b. of resin oil, ahd then 
gradually add, while stirring, 10 lb. or 20 lb. of strong soda 
lye, until a uniform paste is formed. These greases 
are sometimes mixed with blacklead, or rendered 
thicker and more viscous by additions of inert 
weighting materials, such as barytes, china clay, 
gypsum, etc. 

Oven for Case-hardening Cycle Parts.— The con- 
struction of an oven for case-hardening cycle parts is 
shown in sketch. Pig. 1 is a longitudinal elevation show- 
ing the air holes at the sides. These are simply spaces for 
half bricks. Fig. 2 is a longitudinal section showing the 



brushed over with a varnish made of equal parts of 
Canada balsam and spirit of turpentine, and, when dry, 
mounted in the usual way. "With care during the process 
these slides will almost equal photographic ones both in 
transparency and sharpness. The half-tone prints taken 
from photogi'aphs make ' excellent slides. Another 
aitnple method when hymns or diagrams for educational 
purposes are to be thrown on the sheet, is as follows : 
Jfirst get some ground glass out to the required 
size. Braw the diagram, or write the hymn in a 
circle 3 in. in diameter ou paper. Lay the glass on 
the drawing, or writing, ground side upwards, trace 
over the lines with a sharp-pointed F pencil, or with 
Indian ink, using a small mapping pen. Float with 
the Canada balsam varnish by holding the glass at one 
corner, pour the varnish on the centre, spread it by 
rocking the glass backwards and forwards until the 
whole of the glass is covered, and drain off the surplus 
back Into the bottle at one corner. "When dry the slide is 
ready for mounting. 

White Acid for Glass Embossing.— Hydrofluoric acid, 
diluted with water, is principally used in glass etching, 



lllll'- y\' 


III" -llll,,, "."llJi.- ".il 


■111. ■ il 


I -l!l|!lu "'llilh,,^ "lil,^. 41 [, >llllkl' 


lli^ „( 


im^ MJlii'* ..i|((,lil!l, "( ll'lli "HI 


" ■ li!' „ 


l'i|i'" ./ili'i' .MiilHL^ '^llllid 


111", ..illl 


\i"- ' .^fJii ,iil¥" 'i(!l' 


III- "11 


^!|. 1'-, 


Will. ,„illlu ^fli^ 


I. lu 


li!^', -(]| 


¥- 'iirii. 41,11111- ,i! 


'|P "1, 1 


U^ III' 


"Ill'" "Hllllli- 'HI 111 I'" "1 1 11^' 



FlQ. 1 




Fig. 2 



Oven for Case-hardening Cycle Parts. 



brickwork construction, the outside being best red 
ordinary bricks with an inside lining of best quality 
firebricks. The hardening box is shown in position m 
the centre of the fire. Pig. 3 is a cross-section, not, how- 
ever, taken through the air-holes. The size of the oven 
must be regulated by the size of the articles to be 
hardened. A good size for ordinary work would be 6 it. 
or 3 ft. 6 in. long by 2 ft. wide. 

Easily-made Lantern Slides.— To make these, some 
glass cut to the size of the lantern slide, and some 
prints about the size of the slide, must be selected. 
A series illustrating travels or manufacture wiU be 
found a very suitable subject. The pri;it is well 
covered with starch p^ste on the picture side, and 
• laid on one of the pieces of glass, the surplus paste 
being worked from the centre to the edge with a piece 
of cloth wrapped over a <?ork. Great care must be taken 
that the paper adheres to the glass, no air bubbles 
being allowed to remain between the glass and the paper. 
When dry, with a rubber made of a piece of cork covered 
with the finest glasspaper, work the back of the picture 
off until there is only a thin film of paper left, care being 
taken that the paper is not rubbed through to the glass. 
To get an even thickness, hold the slide up to the light, 
when the thickest parts will show dark ; these spots 
must be worked carefully off until the whole surface is 
of an even transparency. If desired, the picture may 
now be tinted with transparent colours. The shdeis now 



but there are several fluorides used lor the purpose- 
Fluoride of ammonia is formed by adding ammonia to 
hydrofluoric acid until it is nearly saturated ; if a slight 
excess of ammonia is added so that the mixture smells of 
it, and then a little more acid be mixed with this, the 
fluoride will be suitable lor glass etching. The fluoride 
of ammonia is placed on. the glass and allowed to dry, 
when the etching effect then becomes apparent. Another 
etching fluid is made by dissolving 25 parts of fluoride of 
potassium, 25 parts of hydro.chloric acid, and li parts of 
sulphate of potash in 100 parts of water. .Another solution 
is made by dissolving 10 parts of carbonate of soda and 
10 parts of carbonate of potash in 40 parts of warm water, 
and then adding 20 parts of concentrated hydrofluoric 
acid and 10 parts of sulphate of potash previously 
dissolved In 10 parts of water. 

Weight of Cast-iron Balls, — To calculate the 
weights, first determine the contents of the balls in 
cubic inches, and then multiply by "26. To find the 
contents of a sphere or ball in cubic inches, cube the 
diameter in inches (that is, multiply It by itself, and 
then the product by itself), and multiply by -526. Thus, 
the contents of a 7-in. ball equals 7 x 7 x 7 x -526 = 
179'6 cub. in., and the weight of the ball is 179-6 x,-26 = 
46-8 lb. The weight of east iron per cubic inch varies 
from ■251b. to ■271b. A simpler method of determining 
the weight in pounds is to cube the diameter in iiiohea- 
and then multiply by '136. 



lOS 



Cyclopaedia of Mechanics. 



Solutions for Silvering Glass.— (a) Dissolve 60 grains 
of silver nitrate in loz. or water, and pour tliis solution 
quioldy into a boiling solution, of 48 grains of Roohelle 
salt in about 1 oz. of water. On cooling, Alter the liquid, 
and make t n to 12 fi. oz. with distilled water. (6) Dissolve 60 
grains of silver nitrate in 1 oz. of water, then add ammonia 
until the precipitate Is nearly re-dissolved, and make up 
to 12 fl. oz., as before. For silvering, equal volumes of 
these liquids are mixed just previous to using. Another 
formula is : (a) Dissolve 48 grains of silver nitrate in 
1 oz. of distilled water, and add ammonia till precipitate 
is nearly dissolved, filter the solution, and make up to 
12 fl. drachms with water, (b) Dissolve 12 grains of 
Eochelle salt in 1 oz. of distilled water, boil, and add while 
boiling 2 grains of nitrate of silver previously dissolved 
in 1 drachm of water, cool, filter, and make up to 12 fi. 
drachms. Mix equal proportions as stated above. 

Covering Circular Frames with Plush.— Take a 

circular piece of plush, 2 in. to liln. larger in diameter 
than the frame, out all round the edges to the depth of 
plush that will overlap the frame ; lay the plush right side 
down on the table without creasing it, apply round the 
front of the frame a touch of glue, which must be strong 
and not watery. Then lay the frame on the plush, and 
strain it tight by pulling it With the hands ; then by 
different stages apply the glrie at the back and overlap 
the overhanging plush, tailing Sin. or 4 in. at a 
time (see A, Pie. 1). Press the plush into contact with 
the wood with a bone paper-knife or piece of wood. When ' 
completed and nicely set, with tailor's chalk draw a circle 
In tlie centre of the plush, then cut it out with scissors ; 
leave a margin of lin. or I in., so as to overlap on the 
rebate of frame. To get the circle easily, a dinner plate 
may be employed as a guide. After cutting out the circle 




FiQ. 1 FiQ. 2 

Covering Circular Frames with Plush. 

■with scissors, cut the inner edge all round to the 
required depth. It requires great care not to cut too 
far, but just so that ■ it will overlap and fit snug (see B, 
Pig. 2). Press it well into the rebate, a little at a time. 

, SelectlnjS Portland Stone. — The chief points in 
Hhe selection of Portland stone for building pur- 
poses depend npon the purpose for which the stone 
is required. There are four distinct kinds, of which 
three are usually sent into the market. The best is 
True Koach, 2 ft. or 3 ft. thick, consisting of a mass 
■of fossils united by a cement composed of carbonate 
of lime, r'i-tinguished from Bastard Eoach by its con- 
taining tue Portland screw fossil ; it is much used in 
engineering works. The Whitbed is the most useful 
Portland stone, consisting of fine oolitic grains, well 
cemented together, with a small amount of shelly matter 
at intervals. It is a good weathering stone, will take a 
fine surface and a sharp arris, and is used for the finest 
ashlar work. Basebed is very similar in appearance to 
Whitbed, but of a less roe-like texture when examined 
through a magnifying glass, and more free from shelly 
matter. Being more uniform in texture and softer to 
work; it is preferred by masons, but does not weather so 
well. It is useful for internal work and carving, and is 

generally known as "best-bed." All stone should be 
lid on its natural bed, but in Portland stone it is not so 
easy to detect this as in more laminated stones. 

Making Marking Inks.— The only really reliable 
■marking inks that will not wash out of linen, apart from 
stamping inks, are those that contain compounds of 
eilver, gold, or platinum. Silver inks are indelible as 
long as the fabric lasts, but they become paler as the 
fabric wears away. Ohloride of lime or eau-de-javelle 
bleaches silver marking ink, the action being to convert 
the black metallic silver into white silver chloride. The 
following recipes are for silverinks -.—{a) Mtrate of silver 
17 parts, ammonia 42 parts, carbona'tfe of soda 22 parts, 

tm 20 parts, sulphate of copper 33 parts, distilled water 
parts. Dissolve the carbonate of soda in 25 parts of 



water, the gum in 50 parts of water, and the nl-trate of 
silver in 10 narts of water. To the solution of nitrate 
of silver add the ammonia and shake thoroughly ; mix 
the solutions of gum and carbonate of soda and add -to 
the silver solution ; finally add the sulphate of copper and 
shake till dissolved, (b) Dissolve 2 dr. of nitrate of silver 
In lioz. of water and add strong ammonia gradually 
until the precipitate which first forms isjust re-dissolved, 
make up to 2 oz. with water, and colour with a little 
indigo e.rtraot, sap green, or any suitable aniline colour. 
It is usual to press a hot iron upon the marking so that 
the ink may decompose and the silver be reduced. 

Making Gold Cardboard Mounts.— The openings or 
slnldngs of cardboard mounts are cut from close-grained 
board made for the purpose. The surface of the out-out 
mount is coated with gilders' thin matt size, which is 
made by mixing fairly strong size with the raw material. 
Generally two or three coatings will be necessary, each 
coat being allowed to dry thoroughly. The surface Is 
next papered down with old emery-papei', washed, 
polished, and finally covered with English gold leaf. 
Much experience is required In this particular branch of 
gilding. The primary cause of failure is in getting the 
matt size and subsequemt weak sizes too strong. 

Apparatus for Distilling Water. — The stm may 
be made from a large Iron Ijettle and the condenser 
from a coil of tin pipe placed in a pail of cold 
water. In the kettle lid bore a 1-in. hole and solder 
into it a bent piece of pure tin pipe. Box-e a 1-in. hole in 
the side of a wooden lard bucket and make a coil from 
three or four turns of the tin pipe ; pass one end through 




Apparatus for Distilling Water. 

the hole in the bucket and cement it in with white lead. 
Stand the bucket on a stool so that the tin coil can be 
connected to the tube in the kettle by means of a small 
piece of rubber tube. The water to be condensed may 
be conveyed to the Ijuoket by means of a small rubber 
tube or a length of compo pipe, and may be syphoned 
away from the top of the bucket by a bent piece of 
compo pipe. The Kettle should be about three-fourths 
flUed vntli tap water through the spout, which is then 
corked, and the kettle is heated on the fire or gas stove ; 
the first small quantity of water which distils into the 
bottle should be thrown away and the distillation stopped 
before the residue is dry. Por drinking purposes, the 
distilled water should be passed through a charcoal 
filter to aerate it. The sketch shows the distilling and 
condensing arrfvugement. 

Making Purse Nets for Catching Babbits.- 

Purse rabbit nets are square worked on a 2-in. mesh, 
using ten or twelve rows of the same number of stitches. 
Flax sewing twine, bought in skeins, is suitable. The 
draw line can be rove thi'ough all meshes round the net, 
and attached to a brass ring for pegging over the rabbit s 
hole, or a ring may be hitched to each corner and the 
line rove through the rings only, in which case the Uue 
is pegged over the hole and not a ring. 

Removing Enamel from Mahogany.-To remove 
enamel from mahogany panels, take a bucketful of 
freshly made limewash and add 2 lb. of common 
washing soda. Ai^ply to the panels with an old brush. 
Several applications may be necessary. As the enamel 
softens, isci-ape olE with a wedge-shaped piece of wood. 
Swill off with plenty of clean water. Should this treat- 
ment turn the panels darker in tone than ..desired, the 
colour may be restored again by wiping over with oxalic 
acid, Joz. to Ipt. of water. Swill off again with clean 
water, then wipe over with common vinegar to remove 
any trace of acid. 



Cyclopaedia of Mechanics. 



109 



Transfer and Re-transfer Papers for Lithograpby. 

—To make yellow transfer paper, mix together equal 
quantities of best flake white and isinglass or gelatine, 
adding sufficient gamboge to give the required tint. Put 
the ingredients in water, and heat them over a slow fire 
until dissolved. Then strain the mixture through a 
piece of muslin to get rid of the coarser particles, and, 
while it Is still quite warm, spread it, by means of a large 
flat camel-hair brush, on one side of smooth, thin paper 
cut to convenient sizes. The paper, when dry, should be 
passed through the press over a heated lithographic 
stone. To make re-transfer paper, mix in tepid water 
one part of best ground plaster-of-Paris with three parts 
of shoemakers' paste free from alum, adding a small 
quantity of dissolved patent glue. Strain through 
double muslin into a ,iar, and spread cool, with a flat 
camel-hair brush, on rather thick paper. 

Replacing a Broken or Cracked Window Pane.— 

Knock out the old glass and putty. This can be done 
with an old knife worn down to about 2 In. or Sin. 
from' the handle. When the knife has made its way 
into the putty, keep it flat against the window frame 
and hit it with a hammer. Work all round the frame in 
this manner until all the old putty is removed, care 
being taken not to chip the window frame by driving in 
the knife too far. The putty being removed, get a little 
paint, and apply it all round the rebate of the frame, and 
after it has dried a little take some fresh putty in the 
right hand and press a thin layer round the frame with 
the thumb. Put in the pane of glass, press it evenly all 
round to bed It in the putty, and fix it on each side with 
two small tacks driven into the window frame with a 
light hammer, allowing the heads of the tacks to protrude 
about J in. Putty the outside of the pane all round and 
bevel it with a sharp knife, resting against the edge of the 




Replacing Broken Window. 

window frame and on the glass in the manner illustrated, 
pressing the thumb against the side A. The figure also 
shows the cut putty at B, the uncut putty at 0, a portion 
of the framing at D, and the window pane at E. The glaz- 
ing is completed when the surplus putty on the inside has 
been removed. When ordering glass to be cut to size, first 
take the exact measurements of the window frame, and 
dedjUCt iVin. from each edge, or Jin. from two sides; 
thus : if the window frame is iSin. by 9 in., the glass will 
be llfin. by Sfin., so that if the glass or frame is not quite 
square the glass will- still fit in, besidse allowing the 
putty to bed against the edges. Putty can be softened 
with linseed oil, and is best kept In a can and covered 
over with the oil. 

Vignetting Apparatus for Photographs. — The 

covers and bottoms of old plate boxes in which 
-a hole with scalloped edges has been cut answer very 
well. They will stand some J in. away from the negative 
—an essential in securing, a soft vignette. The opening 
should be smaller than the size of the desired vignette, 
because the light spreads under the box. For head and 
shoulders, a pear shape is about the best; where thin 
portions of the negative occur under the vignette, cover 
with a piece of cotton-wool, pulling the edge loose. If 
the negative is thin or the light very bright, the whole 
should be covered with tissue paper. 

Polishing the Paneis of a Brougham.— After the 

carriage has the full amount of varnish on, it must stand 
by for at least four months for the varnish to get 
thoroughly hard ; it may then be very lightly faced down 
with pumice-stone and Tvater, and polished up with 
rotten-stone and linseed oil, using a rubber of some 
soft material. Should it have a dull look when finished, 
owing perhaps to too much oil being used, rub over 
briskly with a mixture of equal parts' of vinegar and oil 
applied with a pad of cotton wadding. 

Speeds for Turning and Boring Metals.— For turning 
cast iron the speed of the job past the tool may be 150 in. 
to 190 in. per minute; for wrought iron. 260 in. to 280 in. 
per minute ; for yellow brass, 300 in. per minute ; and for 
chilled rolls, 3 ft. per minute. In boring, the following 
speeds are recommended :— For cast iron, 80 in. per 



minute, and for wrought iron, IV) in. per minute. For 
screw-cutting in steel a suitable speed Is 7itt. per 
minute ; it, however, should depend on the nature of the 
material, Bessemer steel, for instance, being turned or 
screw-cut at a higher speed than cast steel. To deter- 
mine approximately the peripheral! speed of the .iob in 
inches per minute, multiply its diameter in inches 
by 3f, or by 3'14I6, and by the revolutions per minute. 

Gilding Lines on a Boat.— To apply transfer gold leaf 
to gilt lines, rub the varnish down smooth and paint the 
lines to be gilded with equal parts of good oak varnish and 
.iapanners' gold size, into which has been worked a little' 
powdered chrome or ochre- In albout half an hour, when 
" tacky," apply the leaf ; press in contact, and dust off the 
surplus with a camel-hair brush when the whole is finished. 

Converting Oak Branches to Charcoal.— When 

oak branches are so small that useful wood cannot 
be got out of them, perhaps the best way to utilise 
them would be to convert them to charcoal. Small 
branches are, however, not the best for making char- 
coal ; large branches that can be sawn into 3-ft. or 
I-ft. lengthsi are most suitable ; they lie close, andthere 
is not an exce8si'\'e waste during burning. With small 
branches the labour of cutting up will be found to be very 
heavy ; but if they were not out up the branches would 
occupy very much space and the loss during burning 
would be heavy. The branches may be cut up and then 
stacked in a circular mound, as shown in the figui-e. 
First of all, three or four wood piles should be driven 
into the . ground close together, so as to form a rough 
chimney. A ring should be marked around these piles, 
and four to eight shallow furrows should be ploughed in 
the ground from the edge of the ring to the central piles. 




CortVerting Oak Branches to Charcoal. 

The wood may now be stacked around the piles and 
heaped closely till it forms a mound nearly as high as 
the piles and nearly as large as the ring. As a protective 
covering, the whole mound will now have to be 
covered with earth, turf, or wet clay. When this is 
finished, the central piles may be removed, and lighted 
brands placed in the mouths of the furrows, when the 
draught produced by the central chimney will soon 
cause the heap to ignite. The burning should be carried 
on slowly ; when the heat becomes excessive, it may 
be moderated by placing a piece of turf over the furrow 
and damping the earth. When smoke ceases to issue 
from the chimney, turf or earth should be placed over 
the furrows, and the whole of the covering well damped. 
The pile should be allowed to , cool somewhat before 
it is pulled down. 

Cooling Air.— A simple method of cooling air which is 
drawn by a fan from the outer atmosphere is to make a 
frame and cover it with coarse canvas or cloth having 
large interstices, and across the top of the frame carry a 
pipe vrith small holes bored in it ?o that water can be 
made to trickle slowly over the whole of the cSinvas. The 
water could be c6oled with a little ice if necessary. 
There must be a trough or channel to receive the water 
at the bottom of the canvas, and -the frame must be 
erected to fit an opening so that the whole of the 
incoming air will pass through the canvas. Have the 
frame of good size so that the air will not be forced 
through it too swiftly. 

Brush Polish for American Organs.— For a dull 
finish almost any kind of soft gum varnish is gener- 
ally considered good enough; for a bright finish the 
following formula is recommended: Shellac loz., sand- 
arach 3oz., Venice turpentine loz., oil of turpentine 
Joz., camphor 10 gr., methylated spirit Ipt. Carefully 
strain before use ; apply with a camel-hair brush. The 
best results are obtained when the work is clone in 
a hot room. When many coats are applied, sufficient 
time should he allowed for the undercoat to harden 
properly, otherwise " checking" or shrinking, causing a 
cobweb appearance, will be the result. This fault is not 
so apparent on dull as on bright finished goods. 



110 



Cyclopaedia of Mechanics. 



Applying Gold Bronze to Picture Frames Mix 

the bronze with japanners' gold size and turpentine, 
and use it with a good body. The paint will never look 
equal to gold leaf; its durability wiU be increased, 
however, by coating with varnish. 

Door Curtain to Contain Autographs.— A suggestion 
is here given for carrying out a design of an aiitograph 
door curtain, to be worked with coloured silk on a cloth 

f round. , The curtain is 8ft. long by lit. in width, 
'he border is arranged to have a scroll of leaves on a 
stem, the leaves being worked all over so tis to give 




Design for Door Curtain. 



a mass of dark colour. If the leaves are shaded 
green and the stems a rich brown a good effect will 
be produced. Winding round this wreath is a ribbon 
on which the autogi-aph might be sewn ; this, will give at 
pretty appearan ce without detracting from the general 
artistic effect. The scroll across the Upper section ol the 
dado of the curtain is also arranged to take autograplis. 
This dado should be filled in with dark masses of colour. 
The central portion of the curtain might contain the 
outlines and stems of the leaves worked in shaded silk, 
the branches being in shaded browns, and a little more 
fully worked than the leaves. The fruit might be in 
silk of a brighter colour so as to add brilliance to the 
composition. The leaves and fruit may be used for the 



autographs it required, that Is to say if the spaces in the 
border and the top of the dado are not sufflolent ; but It, 
is suggested that the autographs should be placed on the 
^rult first and then on the leaves, as the artistic effect 
will be better. The colouring must be left to the taste 
of the worker, and will depend much on the colour 
of the cloth adopted for the curtain. 

Projection of Spiral Curves.— Assuming a parallel 
spiral, the method to be adopted is the same as that 
for the projection of a helix or single spiral line on 
a geometrical cylinder. The points A, B, o, D, in the 
accompanying illustration, when projected, give the 




Projection of Spiral Curves. 

lines in the elevation, while points E and T give the 
diameter of the cylinder. The left-hand figure shows 
the geometrical outlines, and the right-hand figure the 
shaded result. ' 

Gold-lining Picture Mounts.— To gold-line mounts lor 
pictures, prepare a solution of strong gum arable, and add 
a small quantity of moist sugar ; strain through muslin. 
Placing a ruler where the line is raguired, with a quill 
make a full line of gum. In a fewTninutes the gum will 
become "tacky," and gold leaf, cut ill very narrow strijis, 
may be applied with a tip, dabbed down and skewed In in 
the usual way. This process will give a clean, durable 
line. Gold lines made by applying gold paint turn blaek 
in a very short time. 



Cyclopaedia of Mechanics. 



Ill 



Keeping Water in Gas-holder from Freezing.— 

Mii the water with commercial glycerine, or use a 
solution of calcic chloride instead of water in the tank. 
The most practical way of getting over the difficulty, 
howcTer, is to insert a steam pipe into the tank of the 
holder, and during frosty weather to pass steam through 
the pipe, taking care not to allow the temperature of the 
water to get too high. 

Finishing Piano Gases.— Most Tarnished surfaces 
•can ho got to a dead level and brilliant gloss by iirst 
rubbing level with hair cloth or felt and finest-grade 
pumice powder, and bringing upithe gloss with tripoll, 
crocus, rouge, or putty powder. All inecLualities being 
removed, rub carefully with tripoli and oil, working 
with a circular motion till the surface is perfectly 
smooth and inclines to brightness. Wipe off all 
greasiness and well rub with dry putty and silk, and 
finally finish with flour, still using silk or the palm of 
the hand, which should be perfectly clean. It will re- 
(luire practice to find the most suitable varnish and the 
knack of imparting a brilliant gloss over the large 
■surface of a piano. 

Forming Concrete Window Sills and Heads.— 
Make wooden moulds, wrought inside, of the dimen- 
sions and shapes of the heads and sills, arranging one 
side to be removable, as shown in the sketch. Wedges 
driven through iron straps tighten up the mould when it 
is to be used. For the concrete, take one part by measure 
of Portland cement, one part of clean sharp sand, and 
three or four parts of broken stone, gravel, or broken 




pump is shut off and the gaiige carefully watched. It 
all the fittings are sound, the level of the water in the 
pressure gauge will remain constant. If , on the contrary, 
there is the slightest leak, the lictuid in the pressure 
gauge will gradually sink until it attains the same level 
in both limbs of the gauge. 

Waterproofing Grey Millboards.- Dissolve lib. of 
yeUow so<^p in a gallon of warm water ; also dissolve 1 lb. 
of alum in a gallon of warm watef. Bip the millboard 
for a few seconds in the soap solution, and directly 
afterwards into the alum bath, and then allow to dry. 
Another method of applying the waterproof solution 
Is to add the alum solution to the soap solution, collect 
the precipitate on a piece of muslin and dry it, then 
place it in a bottle and add a little benzoline; the 
alumina soap will gradually dissolve in this, and may 
be thinned with more benzoline so that it can be applied 
to the millboard with a brush. 

Removing Oil - painted Letters from Glass. — 
Brush over the letters a strong solution of caustic 
soda, or a mixture of 2 parts of ^earlash, 1 part of quick- 
lime, and suf&cient water to make it into a cream. Allow 
the llqviids to remain on the glass fora fewminutes, and 
then wash off with water. A second application may be 
made if the first does not remove the whole of the paint. 

Making Soap Box and Tumhler Rack,— Any odd 

pieces of souijd wood f in. or J in. thick may be used to 
make the article illustrated, and the several pieces 
when cut out are put together with round brass-headed 



Forming Concrete Window Sills and Heads. 

brick of, say, 1-in. gauge. Turn these over on a boarded 
platform while they are dry, then, while water is being 
Bprinlded on from a watering-can, turn the whole over 
twice or thrice, taking care not to use more water than 
is necessai-y to bring the cement and sand to the con- 
sistency of good mortar. The mould in the meantime 
should be coated inside with linseed oil or soft soap to 

Srevent the concrete sticking. It is laid on a boarded 
oor, and the concrete is filled in and punned with a 
rammer to well fill the corners of the mould and to ensure 
solidity. Leave the concrete about I in. below the top of 
the mould, and float up this portion with a i^ixture of 
equal parts cement and sand, so as to form a skin of finer 
stuff for the surface that will be exposed to view. The 
mould must now be left undisturbed for two or three 
days, when the wedges may be knocked out and the 
vrindow-head removed. Before being used, the latter 
should be stacked away for ten or twelve weeks— the 
longer the better— to bring out the strength of the 
cement. SiUa can be made in the same way, but the 
moulds are a little more elaborate. 

YeUow Finish on School Furniture.— To obtain the 
yellow or amber tone seen on chairs and stools used in 
schools and clubs, dark-coloured shellac is generally 
used if the articles are finished by French polish or 
spirit varnish. A more prominent colour may be gained 
by rubbing over with linseed oil and yellow ochre. For 
deal goods, size with patent size strongly tinted with 
yellow ochre or lemon chrome. For best-class goods the 
varnish may be tinted with gamboge or madder. 

Testing Gaspipes and Fittings for Soundness.— 
The most satisfactory method of testing the sound- 
ness of gaspipes and fittings is to subject them to air 
Sressure in excess of the pressure of the gas which will 
ow through them. All cocks having been carefully shut 
off, an ordinary pressure gauge is attached, by means of 
a piece of Indiarubber tubing, to the nozzle of a gas 
bracket or pendant, and the cock turned on. Air is then 
forced into the main service pipe by means of an ordinary 
force pump provided with a stop-cock, until a pressure of 
about 4 in. or 5 in. of water is shown on the pressure 
gauge, when the cock in communication with the lorce 




Fig I FIG. 2 

A Soiip Box and Tumblei' Rack, 

screws. The back l)f>ard measures 144 in. long by Sin, 
wide, and the side pieces 12in. long by 51 in. at the 
widest 5!»rt. The tumbler rack is cut from a piece of 
wood 5 in. by 4iin., and shaped as shown in Fig. 4, a 
round hole being cut in the centre to receive the 
tumbler. After all the ijieces are cut to their proper 
shape, rub them well with sandpaper, and fix them 
together. Two or three coats of oil or varnish will help 
to preserve the wood from continual dampness. 

Preparing End Grain Wood for French Folishing. 

--Cabinet-makers finish the end grain of wood ready for 
polishing with a finely set iron-faced plane, and where 
this does not leave the wood sufficiently smooth the steel 
scraper may be used. Some cabinet-makers use glass- 
paper held tightly over a pad isf cork, wiping over with 
glue water or polish to raise or swell the grain during 
the operation. As this dries out it binds the fibres 
together, thus producing a hard, di-yi smooth surface. 

Making Stercotyper's Flong.— Plong may be made 
with two sheets of soft but tough matrix paper and 
four sheets of strong tissue, put together with 
stercotyper's paste. The paste recommended by an 
American authority upon stereotyping consists of 
6Ub. of Oswego starch, 2Ub. of wheat flour, mixed in 
6 gal. of water until all lumps are dissolved. Add 12 oz. 
of common glue dissolved in 2qt. of water, and 2oz. 
of powdered alum. Boil^ stirring constantly, until 
the mixture becomes sufficiently thick. Let it get cold -, 
then take what is required for a day's lise, and add 
one-half the bulk of powdered whiting. Incorporate 
thoroughly, and pass the mixture through a sieve having 
about twenty meshes to the inch. Lay one sheet of the 
matrix paper (previously soaked in water) on a smooth fiat 
surface ; cover with athin layer of tbepaste, well rubbed 
in. Next lay on a sheet of tissue, and smooth it down 
with the utmost care, using either the hand alone or an 
iron roller. Then add paste and paper alternately until 
four sheets of tissue have been added to the two sheets 
of matrix paper. Backing paper may be added after the 
flong has been beaten into form. If placed under a wet 
blanket, the fiong will keep good for several days. 



112 



Cyclopaedia of Mechanics. 



Facing and Staining Picture Frame Mouldings. 

—Patent or glue size and best wMting mixed and 
spread on like paint is generally used ; several coats may- 
be given. Or plaster-ot-Paris and whiting in equal parts 
could be used. When quite dry, smooth down with 
glasspaper or, better still, pieces of pumiee-stone of 
various shapes to fit the hollows, rounds, etc., usi-ng a 
coat of thinned-out whiting and size as a lubricant, 
wiping off the surplus with rag and clean water. To 
stain black, mix a quantity of vegetable black or lamp- 
black in 1 part French polish and 3 parts spirit. Then 
polish with ordinary polish stained an intense black by 
adding a small qviantity of aniline black spirit dye. 

Polishing Razors.— To remove from a hollow razor 
the marks caused by grinding, a glazer is required. 
This may be of wood only, or wood covei-ed with leather 
on the edge, which must be dressed with emery of the 
various grades. The razor must be laid lengthways on 
the glazer. ThS polishing should be effected with 
crdcus powder. The emery powder and oCocus must be 
mixed with mutton suet to a thick paste. 

Re-colourlng Bronzes.— Imitation bronzes, made of 
spelter metal, may be restored by careful washing, 
polishing with soft chamois leather, and lacquering warm 
with best silver lacquer. Ee-bronzing must be done by 
electro deposit. Eeal bronzes may be restored by com- 
pletely covering them in the sand of a brass and copper 
foundry, taking them out from time to time at intervals 
of two or three days, and rubbing them with soft 
chamois leather. When the desired colour is obtained 
they may be lacquered with colourless lacquer; or if not 
lacquered, they will, if rubbed from time to time, improve 
in colour. 

Making Saucepan Covers. — Saucepan covers of 
copper and tin are made In two shapes, as shown in 
section by Figs, 1 and 2. To make a cover like Fig. 1, 



with the buiTlng machine, throw off a flange along the 
top edge of the rim. Now with the same machine take 
up on the covers an edge of such a size that the flange 
of the rim will fit into it. Pene down the edge of the 
cover upon the flange of the rim. Cut out a handle a» 
shown in Fig. i, wire It along both edges, bend it to the 
shape shown by Pig. 5, and rivet on. 

Background for Photographic Portraiture.— For a 

background for full and three-quarter length por- 
traits, a light bluish grey is the best colour. It should 
not be a flat tint, but graduated with soft clouds o" 
various shades. To make such backgrounds requires 
considerable skill. As a makeshift for occasional 
work, the sheet may be stained with coffee to a light 
brown. If it is to receive a flood of light.it may be darker, 
and if in the shade, lighter. The exact tint is best found 
by experience. Or Maypole soap may be used, in which 
case an orange yellow should be chosen. In any case, 
the background should be stretched tight on a frame or 
suspended from a roller with a rod at the bottom. 
Creases are very objectionable. 

Making a Plaster Relief from a Fhotogriiphic 

Negative.— To make a bas-relief in plaster-of-Paris 
from a photographic negative, the process briefly is;a8 
follows :— Soak a sheet of No. i gelatine in a solution of 
bichromate of potash, made by dissolving I dr. of bichro- 
mate in 6 oz. of water j allow this to dry slowly (generally 
taking twenty-four hours) in contact with waxeii or 
French-chalked glass. The glazed surface thus obtained 
is placed in contact with a suitable negative, that is, one 
containing considerable contrast combined with good 
gradation, and exposed to the light. In half an hour, or 
In Ave or six hours, according to the strength of the 
light, a faint image will have been printed on the gela- 
tine. When printed, the gelatine is firmly cemented to 
a sheet of glass with Isinglass or other powerful adhesive, 
and allowed to soak in oold water for about six hours. 




bend a thin strip of metal to the shape of the section ; 
this strip of metal when straightened out flat will 

five the diameter of the circle for the cover in the flat, 
f a number of covers of one diameter are required, they 
are usually hollowed in " tacks " of four or six, according 
to the strength of the material. A wood block containing 
a slight hollow and a bullet-faced hammer are required. 
Hold the edge of the covers over the hollow in the clock, 
and, using the roundest face of the hammer, drive the 
metal down to the hollow, working round the edge with 
regular blows, and continue working round in a series 
of concentric circles towards the centre until the cover 
is hollowed to the desired height. Again commencing 
at the edge, with light, regular blows, go once more over 
the hollowed surface until It is smooth. Now separate 
the covers, and, with a burring machine, throw off a 
flange proportionate to the size required (usually about 
I in. to 4 in.). The cover shown In Fig. 2 is begun in the 
same way as Fig. 1, but when hollowing it Is pitched up 
in a deeper hollow with the heel of the hammer, or with 
a hammer specially made for the purpose, until the ridge 
shown in the illustration is formed and the outer edge is 
left all puckered. Assuming that the cover is to be 
finished without the use of a swage, the edge on the top 
of the cover should be worked up sharp with a mallet 
upon a bright round head ; then form the side of the 
ridge, worked round carefully, with a square-faced 
hammer (the front edge of which has been rounded off) 
upon a bevel stake. The outer flange may then be 
thrown off upon a briglit anvil, using a mallet to remove 
the puckers, and a round-faced bright hammer to work it 
down to the shape. The cover should then be planished 
smooth and true, and the top also planished to finish it. 
From this point the working of botn covers is the same. 
Cut from an arc of a circle, equal in length to the 
circumference of the body the coyer is to fit, a rim about 
I in. deep, with allowances for flanging and edging, as 
shown by Pig. 3; then work over an edge along the 
dotted line on the inner curve, and flatten this edge 
down so as to stiffen the rim. Turn the rim round, fit it 
to the body, and solder it together at the ends. Then, 



afterwards soaking for a further time iu a 1 in 4 solution 
of citric acid, and finally in water. When the utmost 
possible amount of relief has been obtained, the super- 
fluous moisture is carefully removed with the edge of a 
blotting board, and oil is poured over the gelatine 
mould, and then drained off. The gelatine relief is 
then placed in a dish, and the plaster poured over it 
and allowed to set, after which the relief may be pulled 
off. The relief thus obtained is generally rather false 
owing to differences in colour— particularly it isoohro- 
matic plates are not used— being grossly exaggerated. 
Huch may be done by skilful retouching. 

Gold Veins In Book Bdge Marbling.— The gold 
veins in marbled paper, or on the marbled edges of 
books, may be produced as follows ;— Let the rest of 
the marbling be thoroughly dry. Then beat well 
together 1 part white of egg, 1 part spirit of wine, 
2 parts water. Let the mixture get clear, then wet a 
small portion of gold powder (shell gold will do), mixing 
well with the finger, and apply with a small camel-hair 
pencil. Let it get thoroughly dry before burnishing, 
which should be done with a polisher made only 
moderately warm. The beginner should make several 
experiments before proceeding with the actual work. 

Waterproof Dressing for Overalls. — Unbleached 
calico or drill sheeting is generally used for making over- 
alls i all the seams should be double seam. For a dress- 
ing, really good boiled oil is perhaps the most durable, 
though some sailors prefer raw oil, but both take a long 
time to dry and are apt to become sticky. The following 
is safer for oilskins not In constimt use : boiled oil 8 
parts, turps 2 parts, and melted beeswax 1 part. Warm the 
oil, add the wax, stir in the turps, and apply warm. The 
first coat must be well rubbed In. In an hour or so wipe 
off any surplus that may have drained down to the lower 
edge. When thoroughly dry, add equal parts of boiled oil 
to the former mixture, and lampblack or ochre as 
desired. With this paint give the material two more 
coats, letting each dry thoroughly in a cool, shady place. 



Cyclopsedia of Mechanics. 



113 



Remedy for Smoky Chimney.— The most prolific 
cause of smoking with open ranges is the large open space 
that exists over the range and forma the mouth o£ the 
chimney. The draught in these ranges is not very keen 
at the hest, and the large area allows quite cold air to 
rest there and to pass freely into the chimney, with the 
worst possible results on the up-draught ot smolte and 
heated air. This is OTercome by the use of a blower, 
which is a sheet of metal carried across the front of the 
range opening at the top, from jamb to jamb of the 
mantelpiece. This causes all air entering the chimney 
to come closer down to the fire and recei¥e warmth, for 
while cold air impedes the up-draught, hot air acceler- 
ates it. A cranked metal pot will often prevent the 
down-draught, whilst a blower .will stop the general 
smoking. The blower can be made temporarily of card- 
board or paper to find the depth req.uii'ed. 

How to Make a Metalworkers' Mandrel Dolly.— 

A mandrel dolly is made by first fixing the mandrel 
securely to a strongly made bench, by means of iron 
clamps passing over the square end of the mandrel, and 
holding them in position by nuts and bolts, as shown. 
On the end of the hammer shaft an iron hinge is fixed, 



fill it, so as to allow of frothing. The lyes are made by 
, adding caustic soda to water. Two lyes are often em- 
ployed, and usually three, one at 10° Tw. (4 per cent.) , one 
at 16" Tw. (6i per cent.), and the other at 24° Tw. (8i per 
cent.). The fat is run into the pan, and the weaker 
alkali is gradually added while boiling; the stronger 
alkali is then added, and the mass boiled for several 
hours until clear. The pan is then allowed to settle, salt 
added, and, after thorough stirring, the waste lye may 
be run from the bottom of the pah. The strongest lye 
may now be added gradually, boiling and stlrrinK 
thoroughly until the soap boils clear; then allow to 
settle again, and run off the soap into frames, taking 
care that any waste lye at the bottom does not go along 
with it. The strength and amount ot the different lyes 
vary, but on the average 151b. to 161b. ot caustic soda 
are employed for 100 lb. of fat. 

Stltclilng a Square Edge to the Cushion of a Couch. 

—To stitch up the front edge of a couch seat so as to 
procure and retain a fine point, the tools required are a 
double-pointed 8-in. mattress needle, a reeulator, which is 
something like a broad flat packing needle, and a ball ot 
strong twine. Insert the regulator about 4 in. from the 




How to IVIalie a MetalworkeiB' Mandrel Dolly. 



and when this is done, the hammer should be held fiat 
and true in position upon the mandrel, and the position 
at which the vertical part of the hinge is to be fastened 
to the upright carefully marked. Then secure the hinge 
in the required position. Now fasten a stont lath of 
ash, to act as a spring, at the top ot the, upright beam to 
an iron bracket, as shown, and over the opposite end of 
the lath fasten a leather strap ; then fasten the lower 
end of the strap round the hammer shaft, so that the 
hammer is heldT suspended about 8 in. above the work. 
When using the hammer, grasp the shaft close to the 
hammer head, and swing it down against the resistance 
of the ash lath to produce a blow upon the mandrel. 

Paste for Laying Linoleum and Oilcloth. — To 

make cheap fiour paste suitable for laying linoleum and 
oilcloth, mix rye nour with a little cold water, then add 
boiling water, well stirring the paste while the water is 
being poured. Melt some glue size and add to the paste 
while both are hot. Stir well. The more size is added the 
greater the strength ot the paste. As a rule, " Inlaid " 
linoleums require very strong paste. A little alum 
dissolved in the paste is a preservative. It the paste is 
too thin, boil it, to evaporate some of the water. 

Converting Bacon Cuttings Into Soap.' — The 

fat is first rendered in a large cylinder vrith an 
inlet for steam, exits for water and melted fat, man- 
holes for charging and withdrawing fat, a false bottom 
for the latter to rest on, and a safety valve weighted 
to a pressure of two or three atmospheres, that is, 
30 lb. to 45 lb. per square inch. The rendered fat is then 
run into cold water and removed for soap making, which 
la usually carried out in immense pans heated by fire 
and steam, either alone or together. The amount of 
materials put in the pan should not more than two-thirds 



front edge of the seat, and work the flocks.or whatever 
the stuffing material is composed of, well up to the edge, 
pricking the regulator in about every 6 in. The first 
stitch is known as the blind stitch, as it cannot be seen 
on the top of the seat. Thread the needle with twine, 
pass it through the front a little below the stuffing rail, 
and out at the top ot the seat about 4 in. from the front 
edge. Without pulling the needle right out, back it out 
again on the front 1 in. beyond the point at which it was 
first inserted. Repeat this operation along the whole ot 
the front, pulling the stitches tight ; that will draw all 
the fiocks within the stitch on to the front edge ot the 
stuffing raU. Now insert the threaded needle again 
about i in . higher than the last stitching ; pass it through 
the top of the seat, and re-insert it about 1 in. farther on, 
stitching through backwards and forwards, letting the 
needle come out midway between the last stitches ; puU 
the stitches up tight, and repeat the process as often as 
necessary, every row of stitches coming nearer the edge, 
until a fine point has been obtained. The edge, when 
finished, is similar in appearance to two or three coils of 
rope. Should the edge be very soft, or give in the middle, 
the stitches will be found to be slack or the rolls not 
stuffed firm enough. Take particular care to use the 
regulator before every row ot stitches. 

Cement to withstand Paraffin Oil.— Glue is one of 
the best materials tor withstanding paraffin or any 
other oil. Another cement is made by dissolving 1 part 
of caustic soda in 5 parts of water, and boiling with 
3 parts ot resin tUl dissolved. Afterwards stir Into it 
about halt its weight ot plaster-ot-Paris or chalk, and 
use at once, as it hardens rapidly. This cement 
would take the place ot red lead or white lead. Common 
yellow soap is also recommended tor withstanding 
paraffin. 



114 



Cyclopaedia of Mechanics. 



A Table Book-rest.— Procure a Ijoard 13 In. wide and 
4in. thick, planed smooth and as free from knots as 
possible. A piece 15 in. long, shaped as shown in Fig. 1, 
forms the board A (Figs. 1 and 3). The star at the top of 
the board may be cut with a fret-saw. Eub with glass- 
paper and make all the edges quite smooth. Out two pieces 
Bin. by 2Sin. for the feet, and shape as shown in Fig. 2. 
When smoothed, screw them to the back of the board, in 
the position indicated by the dotted lines, at B (Fig. 1) ; 
see also B (Fig. 3). Procure a piece of wood 11 in. long 
by Uin. square for the rest (Figs. 1 and 3), bevel the 
edges as shown in Fig. 1, and secure It to the front of the 
board by screws put in from the back. Procure two pieces 
of sheet brass 2in. long by i in. wide, and about Ain. or 
iln. thick. Drill a hole about ^in. from one end of each 
strip, file the strips to the shape shown in Fig. 1, and 
screw them to the rest with round brass-headed screws. 
Cut one piece of wood 10 in. by 2 in., and screw it to the 
back of the board Sin. from the top, as indicated by the 
dotted lines at D (Figs. 1 and 2) . Out another piece of 
wood measuring 124 in. by 3 in. (or the support E (Pig. 3), 
and secure it to the centre of the oi-oss-piece D with a 
U-in. back -fold hinge, as shown in the illustration. 
Procure a piece of fancy cord, secure one end to the 
board, insert the other end in a small hole bored through 
the support, and make a knot to keep it in place, as 
shown at P (Fig. 3). Make aU the edges and corners 
quite smooth. The book-rest will look very well indeed 



by drawing the slide, which brings the spirit lamp In 
contact with the vapour from the oil cup ; when flashing 
occurs the temperature is noted on the thermometer" 
Immersed in the oil. Water is used in the bath for oils 
which flash below 100" 0. (212° F.), butfor oils which flash 
above that temperature mercury must be employed. 

Heating Cylinder from Two Fires.— A breakfast 
room grate and a kitchen range, it the two flres are back 
to baoK, can be utilised to heat a cylinder. There must 
be a boiler in each fire, the saddle boiler In the range 
being connected to the cylinder in the usual way, and 
the boiler put in the grate fire will be connected either 
to the pipes from the range boiler or independently into 
the cylinder. By this arrangement either boiler will do 
all that it is capable of doing towards heating the con- 
tents of the cylinder, and they will work separately or 
together without trouble, and without the use of stop- 
cocks or anything of this kind. Bfo alteration is needed 
to the flues of either stove. 

Use of tbe Optical Square.— This is an instrument 
2 in. diameter by Jin. thick, to be held in the hand and 
arranged as shown in the accompanying flgure, in which 
A is the sight hole where the eye is placed, B and C are 
openings in the rim through which rays of light can enter 
from poles at D and E, only farther ofE ; P is a glass halt 
silvered and half plain, the junction line being in the 
plane of the instrument : Q is a whole mirror. In using 






J 


y//.m 



How to MELke a Book-rest. 

If made of walnut and finished by French polishing. 
When in use, it is placed upon a table, and the support 
adjusted by means of the cord. 

Rcgllding Soldered Joints of Plated Goods.— 

An electro-gUdlng solution made as follows is re- 
quired: Dissolve loz'. of potassium cyanide in Ipt. of 
aistllled water made hot in an enamelled iron saucepan ; 
suspend in this two strips of pure gold attached to 
copper wires and connect to a battery of two Bunsen or 
Daniell cells for an hour or more. Eemove the strip 
of gold attached to the zinc element of the battery, ana 
substitute a strip of silver. If this takes a nice gold 
colour, the solution will be fit for gilding. If not satis- 
factory, pass the current through the hot solution 
untU it will gild properly. The cost of cyanide and 
water will be only a few pence. 

Ascertaining Flash Point of Oils.— The flash point 
of oils is determined in two ways— by the " open 
test" and by the "close test." By the first 
method a small porcelain or metal dish Is partly filled 
with the oil and placed on a sand bath heated by a 
burner; a thermometer suspended with the bulb in the 
oil registers the temperature. As the temperature rises 
a lighted taper is quickly passed over the surface of the 
oil, and when a taint vaulshinfe flame Is noticed, the 
temperature is read oft-: this is the flash point. For the 
close test method the apparatus devised By Prof. Abel is 
employed ; this Is fully described in the Petroleum Act 
of 1879. The apparatus is really a jacketed copper water- 
bath heated by a burner ; the oil Is contained in a small 
cup fitting into the lid of the bath, and there are thermo- 
meters in the bath and oil cup. The oil cup is covered 
with a lid and a slide, and hinged to it Is a small spirit 
lamp. When the slide is drawn out the spirit lamp Istilted 
over the oil cup so that the flame is right over one of the 
holes in the lid, and on replacing the slide the lamp 
assumes Its vertical position again. The testing is done 



An Optical Square. 

the instrument for sighting poles as shown, it would be 
held in the left hand j with the eye at A, the pole D would 
be seen through the opening B and the plain part of the 
glass P ; the observer being at the point where a right 
angle would be measured between DH, EH. Rays of 
light from pole E will reach mirror G and be reflected 
from there to the silvered part of glass P and thence to 
the eye at A, so that the glass P will appear like Fig. 2, 
the piece of pole 1 seen by direct vision being exactly 
over the piece of pole K s^en by reflection. It in using 
the instrument the poles do not coincide, the station of 
the observer must be shifted until they do, or as an 
alternative one of the poles must be shifted. If the poles 
appear to poincide at the junction of the glasses but 
not to be in a straight line, it will be due to one of 
the poles being at a higher level than the other. 

Making Blowers for Register Stoves.- Commence 
hollowing the semicircular blower by working round 
the circular part with a series of regular blows from 
a bullet-faced hammer, and holding the edge of the 
metal over a shallow hole in the hollowing block. 
This will curve the metal to a slight depth round the 
edge. Then bend the metal about lin. from the edge 
along the straight part, so that it makes a sharp angle ; 
this win keep the bottom stiff while the remainder of 
the hollowing is done. Now commence on the circular 
part again, and work round from the edge in towards 
the centre, in a series of concentric circles, working it 
in a deeper hole if necessary than that used for com- 
mencing in. When the blower is hollowed to the depth 
necessary, go over the hollowed part again v?ith a series 
of light regular blows until it is rendered smooth. 
Knock out smooth the break along the bottom, and 
then bend the ends round to the same curve as tbe 
hollowed part. A tew blows from a flat-faced hammer, 
delivered upon the centre or flat part of the blower, may 
be necessary to set It so that it will be free from twist. 



Cyclopsedia of Mechanics. 



115 



Value of Gold and Silver. — Gold has a, fixed 
market value per ounce which never alters. Pure 
gold (24 carat) is worth &i 5b. per ounce troy ; 22-oarat 
gold (guinea gold or wedding-ring gold) is worth 
£3 17s. lid. per ounce ti-oy j 18-carat gold is worth 
£3 3s. 9d. per ounce ; 15-carat gold, £2 13s. IJd. ; 12-carat 
gold (half gold, halt alloy), £2 2s. 6d. per ounce; 9-oarat 
gold (the lowest quality that is hall-marked in England) 
IS worth £1 lis. lOJd. per ounce. The value of silver 
fluctuates according to the market ; it has been worth 
5s. per ounce troy, and it has fallen to 2s. The London 
market value of silver will be found in most daily papers 
under the heading "Market Keports," amongst the 
" London Metals." 

Canse of Clicking Noise in Hot-water Pipes.— The 

clicking noise that proceeds from hot- water pipes after 
hot water has been drawn is caused by the expansion of 
a pipe (or pipes) when suddenly heated. If the pipe is 
cold, as is probably the case, before water is drawn off, it 
becomes suddenly hot when a tap is opened, and begins 
to expand lengthways. Wherever the pipe is so tightly 
fixed that free expansion is impeded, the resistance is 
overcome with a little jerk that causes the clicking noise. 
Pipes laid under floors across joists, where notches are 
never cut very deep, often give out the noise described. 
The same thing sometimes happens with circulating 
pipes as weU as branches, though, in this case, it may be 
the sudden cooling and contraction of the pipes that 
cause the noise. 

Purple Stain for Wood.— To make a purple stain, 
obtain lib. of logwood chips or ilb. of logwood 
extract. Jib. of pearlash, 2oz. of powdefed indigo, and 
3 qt. of water. Boil the logwood till the full strength is 
obtained, then add pearlash and indigo. The stain may 
be used hot or cold. 

Fitting Worm Screws and Raised Frets to a 
Banjo.— To fit worm screws and raised frets to a 
banjo, get a pair of plates with machines fitted, and 
adapt them to the head, of the banjo by squaring the 



of each side may be cut away. Everything must be dono 
systematically, working at opposite sides in turn. Waste 
wood should then be piled round the base in sufficient 
quantity to ensure that the wood studs will be burnt 
through, and lighted at several points. A couple of 
look-out men during the operations should be posted 
sufficiently far off to command a view of the chimney 
from two directions at right angles, and near enough to 
warn the men if any signs of prematare falling were to 
occur. Local circumstances and the construction and 
condition of the chimney stalk may render some varia- 
tion on the above method desirable. A cheaper method, 
and one that would probably be satisfactory in the 
hands of au expert in explosives, would be to explode a 
small charge of dynamite in the bottom of the shaft, 
or to' bore holes round the base and insert charges of 
gunpowder, to be fired simultaneously. 

Tuck Pointing Brickwork : Methods and Materials. 

—The ordinary process of tuok-pointlng is as follows. 
The joints of the woi'k to be pointed are raked 
out to the depth of iin., then filled in with stopping. 
If the stopping Is not coloured, all the work Is 
rubbed over with a soft good-coloured brick, so 
that the joints may look like the face of the bricks. 
A small groove is formed along the centre of the 
jpint, and, the mortar having been allowed to set a 
little, this groove is filled up, for white tuck pointing, 
with white lime putty, till a raised line of putty projects 
beyond the face of the joint (see illustration). The 
edges of the white line are cut perfectly parallel by the 
pointing knife held against a straightedge, and drawn 
along so as to remove the superfluous putty, leaving a line, 
about i in. to i In. in width, standing out beyond the face 
of the work as far as it is possible to make it. This gives 
the work the appearance of being a good piece of brick- 
work, executed with square-edged bricks and clean white 
joints. The effect, however, does not often last long, the 
first sharp winter usually playing havoc with the pro- 
jecting joints. If the pointing Is to last, it is better to 
use the ordinary wesLthered joint executed in cement. 



?K«W 






Fitting: Worm Screws to a Banjo. 

" scalloped " sides and slotting the present hole's quite 
through, similar to the sketch, liaised frets are fitted by 
making a "saw cast," putting in a little powdered 
shellac, heating the fret-wire, and pressing it into place. 
Specially prepared fret-wire can be obtained for the 
purpose. 

Varnish for Cork Frames.— For a varnish suitable 
for cork frames intended for indoors, there is 
nothing to equal spirit varnish, which consists of 
methyQited spirit Ipt., shellac 4oz., and resin 2oz. ; it 
dries quickly and gives a glossy finish : a cheap quality 
will do. Apply in a warm room, and well stipple it in all 
crevices. Thin out with spirit for the first coating, but 
use it thicker for the second or finishing coat. 

Roughcasting Walls.— The walls are first plastered 
with lime and hair mortar, having, for the best class of 
work, some cement added to improve it. After this has 
set, a second coat of mortar, mixed so as to be fat, is 
spread as evenly as possible over the last coat, and while 
this is quite soft the stones to be used are dashed forcibly 
against the work, to which they adhere. Care should be 
taken to see that the sand and stones or pebbles used are 
free from dirt, and if any clay is found mixed with the 
sand it will require washing. The stones should be 
screened so that they will be of about the same size. 
Sometimes a coat of lime-white and sometimes ochre is 
used for colouring the roughcast. 

Felling a Ugh Chimney Shaft. — To ensure that 
the stalk shall fall in a narrow compass, it will be 
desirable to fix three guy ropes from the top, equally 
divided round the circle, and made fast at a distance 
from the base of the shaft at least equal to half the 
height. Openings should be cut in the brickwork of 
the base on opposite sides, and 9-in. by 9-in. studs 
inserted, about 4 ft. long, between 9-in. by 3-in. plates 
running through the thickness. Before making the 
openings, 9-in. by 3-in. raking shores both ways should 
be fixed at each corner of the base. Two openings in 
each side, with a brick pier left between, would, in the 
writer's opinion, be required ; and when this is done, if 
there is no sign of cracking or settlement, and the studs 
are taking a good bearing, the Intervening pier in centre 



Tuc^ Pointing. 

White lime putty is made of pure lime slaked with witer 
and strained off while hot (the consistency should be 
about that of cream) ; it is then mixed with washed silver- 
sand— but a better material is marble dust— in the propor- 
tion of 2 or 3 of sand to 1 of lime. Blue pointing mortar 
is made by using sifted cupola or forge coal instead of 
sand, and black pointing has lampblack added to the 
other materials, small sections at a time should be pre- 

gared for pointing, for if the mortar is allowed to set 
ard, a groove for the white line will be difdcult to make. 
To colour the work tor yellow bricks, use 1 lb. of green 
copperas to about 5 gal. of water ; for red bricks, lib. of 
Venetian red and lib. of Spanish brown to ligal. of 
water ; the quantity of colour must be varied according 
to the tint required. 

Watch Carried In the Pocket Losing Time.— 
All watches (except extremely fine ones) lose to a 
certain extent in the pocket and go faster when lying 
horizontally, the difference varying from thirty seconds 
to one minute per day. It is caused by the more free 
vibration of the balance when poised on the end of one 
pivot only than when resting on the sides of two pivots, 
as it does when in the pocket. If the difference in a 
watch exceeds one minute per day, most likely the 
balance is not truly poised— that is, It is heavy at one 
point of the rim— and acts more or less as a pendulum 
when the watch is vertical. To remedy it, remove the 
balance and take off the hairspring. Then place the 
balance with its pivots resting on two finely polished 
straightedges, on which it can roll freely and be tested 
for poise, any fault being corrected by means of the 
screws in the rim (if it has them) or by filing, if it is a 
plain balance. Poising tools are sold for this especial 
purpose. 

How to Make Silver Bronze Powder. — The 
best silver bronze is made by mixing silver leaf with 
honey or gum water, and grinding to powder in a 
mortar^f ter which the powder is washed with water and 
dried. For a common silver bronze, melt together 1 lb. of 
bismuth and 1 lb. of tin, and add i lb. of mercury. Pour 
the amalgam on to a cold surface and grind to powder in 
a mortar. Another form of silver bronze is simply pul- 
verised white mica. 



116 



Cyclopsedia of Mechanics. 



"Marine" Glue.— Marine glue U made from 1 part 
of indiarubber (cut into shreds) and 12 parts o( coal-tar 
naphtha i these are kept in a bottle in a warm place 
and shaken from time to time till the rubber is dis- 
solved ; then 20 parts of powdered shellac are added, and 
shaking is continued until the mass becomes pasty. It 
is then poured on to a cold surface, allowed to solidify, 
^ and then broken up into small pieces, which should toe 
melted and applied as thinly as possible while still warm. 
Great cai'e must be taken in making this oeaient, as the 
naphtha Is very iuJlammable. 

Making a ChllA's Chair.— The strong useful chair 
illustrated below is suitable for children in their 
teens, and will stand wear and tear for a great 
many years, provided it is made from a hard 
wood. All the spindles can be made with spolceshave 
and plane, and also the top for the back and seat if 
desired; or they can be obtained cut to pattern for a 
few pence extra from any timber merchant. For the 
seat, a piece 16 in. by 12 in. by IJ in. is required, cut to the 
shape shown at Pig. 3. The underneath part can be left 
in the rough. Bore through it iif teen holes 1 in. diameter 
in a slanting direction, at distances given on Pig. 3. Into 
the holes at the sides nt eight spindles 10 in. long (9i in. 
when trimmed flush), J in. diameter, tapered at the ends 
so as to fit tight in the holes made for them ; these spindles 
form sides for arm-rests. For the arm-rests two pieces are 
required, 12iin. long, 14 in. wide, and iin. thicK, cut to 




left on them. The scale can only be got rid of by 
grinding on a large stone, or otherwise by the use of 
pumice-atone and water, followed by ij^'essing off with 
Tam-o'-Shanter stone. For cleaning up after firing, try 
a solution of about 1 part of nitric acid in 6 parts of 
water, slightly heating the brass before plunging it in, 
leaving for a minute or two, then brushing with a stiff 
worn-out brush, and finally washing in clean water and 
drying in hot sawdust. The solution may be bottled 
and used over again, adding a little fresh acid from time 
to time. 

Strength of Sheet Iron Water Tanks.— Bectangular 
tanks are tested as follows: ifSri"-' lOlb.; iin., 51b. per 
square inch. The corresponding values for cylindrical 
tanks are 401b. and 2.51b. per square inch. The cylin- 
drical shape is almost invariably used when the pressure 
exceeds about 121b. per square inch. The resisting 
powers of all tanks that are not spherical or cylindrical 
are increased by the use of internal stay-rods. 

Photographic Mountants.— The best of all photo- 
graphic mountants is starch. Place a teaspoontul' 
of crushed starch in a teacup and mix into a thin 
cream with cold water, then, whilst stirring, add 
boiling water till the starch thickens. Allow to cool, 
remove the skin from the top, and the starch is ready 
for use. When more than two days old it does not answer 
well. The following have also been recommended, and 
will keep a considerable time. No. 1.— Dissolve 1 oz. 
of white dextrine In 3 oz. of water, add 1 oz. of powdered 
starch, and strain ; then warm until the solution becomes 
clear. Now add about 40 gr. of white sugar and about 




i-.. Fig 2ri— ^^ 
How to Make a Child's Chair. 




Fig 3 



the shape shown at Pig. 4 ; through ttese are bored five 
holes, four holes f In. diameter, and one hole J in. 
diameter, at distances shown on Pig. 4, starting from the 
front part of the arm Into which the spindles fit. The 
top tor the back is cut from 14-in. wood to the shape and 
measurements shown at Pig. 5, and has holes bored half- 
way through to receive the back spindles, of which seven 
are required, 20 in. long, i In. diameter, and tapered at 
the ends to fit into i-ln. holes. For the legs four 
pieces are required, 154 in. long, I in. diameter, and 
tapered a little smaller at the top to fit In the holes 
made for them In the seat, which should be J In. diameter. 
Pitted In the sides of the legs are two spindles, 104 in. 
long and }in. diameter in the centre, tapered at each 
end to iin. diameter; into these is fitted across a 
spindle 15 In. long and 4 in. diameter. Before fitting the 
legs Into the seat, fix the spindle into the legs, and then 
the legs into the seat; the legs are 14 in. long when 
trimmed flush with the seat • also trim the back and arm 
spindles flush. The arm-rests must be fltted on before 
the top of the back, so as to allow two of the back 
spindles to pass through the ends of the arm-rests. 
Then flt on the top of the back, and the chair Is ready 
for decoration by paint or enamel. The measurements 
could be altered so as to make the chair suitable for an 
adult. 

Cleaning Sheet Brass after Annealing.— Large 

sheets of brass should be annealed In a properly con- 
structed muffle or furnace ; small pieces may be done In 
an open fire of cinders or small coke, not too hot. Heat 
the plates to a dull red heat in the dark, and leave to cool 
off. They require careful watching, or they will burn. 
Some brass plates, after being rolled, annealed, and 
washed in sulphuric acid and water, have a red scale 



halt a dram of a 10 per cent, solution of carbolic acid. 
No. 2.— Soak 1 oz. of gelatine In 4 oz. of water for an hour 
or so, then add i oz. of chloral hydrate, keeping the 
solution hot during this addition. Or a good man is to 
dissolve the chloral hydrdrte in a portion of the water, 
and then add whilst hot. A few drops of a saturated 
solution of carbonate of soda should be added to render 
It faintly alkaline. This mountant is extremely adhesive 
and does not penetrate the paper, so that it is specially 
suitable for mounting glazed prints, which lose some 
of their brilliancy when the mountant is very wet. 

Chemical Fire Engine.— The chemical fire engine is 
fltted with two tanks, one of which contains a solu^ 
tion of bicarbonate of soda and the other sulphuric acid. 
By allowing the acid to flow into the bicarbonate, 
carbonic acid is evolved, and the pressure induced 
forces the liquid through the hose pipe. When the- 
liquids are mixed there Is present a solution containing 
sulphate of soda holding carbonic acid In solution, and 
this has been found very effectual In putting out fires. 

Preparing Moonlight Scenes for Diorama.— The 

hi^h lights should be cut with a sharp knife, each cut 
being horizontal, and from Iin. to 3ln. m length. Take 
care the cuts do not run into each other. The path of 
the moonlight across the water should be cut thickly 
and close, especially at the horizon, getting broader as 
the bottom of the picture is reached. A few outs to 
represent ripples about the other part of the water wuj 
give a nice effect. A good light must be placed behiha 
the picture, the light in front being very dim. For 
a small subject there Is no necessity to cover the cuts 
with gauze ; the movement of the painting as it travels 
along will give the shimmering effect. 



Cyclopaedia of Mechanics. 



117 



Lens for AH - round Photographic Worii, etc.— 

For all-round work with a whole-plate camera, procure 
a rapid rectilinear of about 94-in. focus by a good 
maker, such as Boss, Dallmeyer, Wray, o? Taylor. 
The components of the lens should he of different foci, 
*o that -varying sized plates may be used, or different 
angles included. A lens of this kind may be made to do 
duty for a variety of purposes. For example, quoting 
from one maker's list, a lens of 9i-in. focus covering a 
whole plate at full aperture (f/e-S) will, when stopped 
down to//U'3, cover a 10-in. by 8-in., or to f/22-6 a 12-in. by 
10-in. The lens is composed of two compound lenses of 
14 in. and 19Un., covering plates, when used at flVi-&, of 
10 in. by 8 in. and 13 in. by H in. respectively. The lens 
is listed at £16 10s. Thus, tor architectural work, where 
a doublet is most needed, the lens might be used in its 
entirety, and on a 12-in. by 10-in. plate it in a confined 
situation. "When portraits or landscapes where good 
perspective is an important consideration are attempted, 
|the single components or a smaller plate must be used. 
lit must be borne in mind that the value of the stops 
varies with the lens. For example, a stop about 1 in. 
diameter, which, when used with the lens entire, was 
valued at f/8, would become, approximately, ft22 and fl32 
when used with the single lenses. Lancaster's combina- 
tion reotigraph is on the same principle, and costs £2 10s. 
Hollowing the Underside of Ridge Roll.— To 
hollow the underside of a ledge for covering the joint 
of a roof as shown in the accompanying sketch (Fig. 1), 



(probahly about sixteen) on to a quarter-plate piece of 
clean glass that is free from scratches and bubbles, and 
squeeze well into contact by placing a sheet of blotting- 
paper over the back and driving out air bubbles. The 
prints must be placed face downwards on the glass. Put 
the glass in a printing-frame and hang it flat against a 
wall in a full light. Extend the camera to twice the 
focus of the lens and place it at the same distance from 
the printing-frame, measuring both ways from the stops. 
HaTing focussed very accurately in the centre, stop 
down until the outermost pictures are sharp. Use 
slow plates and give two exposures, one double the 
other. These negatives should be enlarged on to 
bromide paper 24, in. by 18 in., which will give 6 in. to 
each picture. Pictures as nearly the same as possible 
in tone should be chosen for enlarging together. 
Bach picture could, of course, be enlarged from a 
separate negative, but the expenditure of time and 
money would be considerable. "When developing a 
sheet of this size the developer can be applied with a 
large pad of cotton-wool or a flat soft brush, first wetting 
the print with water to slow development. 

Height of Domestic Hot-water Expansion Pipe. 

—The expansion of water in these apparatus never 
exceeds 1 in 30 ; that is, the top water line in tlie 
apparatus never stands higher than the cold-water 
line in the cistern which feeds it, more than 1ft. for 
each 30 ft. vertical height to which the apparatus 
extends. It is seldom that an apparatus of this kind 




Fia. 3 



How to Hollow the Underside of 'Ridge Roll. 



the end of the piece of wood should be marked out 
and a small plough groove made, as shown at Fig. 2. The 
greater part of the superfluous material can then be cut 
away with a mallet and chisel. The surfaces can he 
finished with a broad rebate plane or, better still, by a 
jack plane (or panel plane) with a side slip, which takes 
off as shown at Figs. 3 and 4. 

Obtaining Smooth Surface on Glass Balls.— To get a 
perfectly smooth surface on glass balls direct from the 
moulds, remove the outer hard skin of glass by revolving 
the balls with a little fine emery powder and water; 
after that they will grind themselves smooth. If a 
polished sui'face is I'equired, the balls ivill have to be re- 
volved with plenty of dry rouge, colcothar, putty powder, 
or "other rather soft polishing powder quite free from grit. 

Darkening Light Brown Leather Shoes.— To darken 
a pair of light tan shoes, give them a couple of coats of 
Propert's dark staiu, and afterwards polish with the 
darkest brown cream that can be obtained. It the leather 
has not been croained before, a couple of coats of the 
darkest brown shnde of Dolly dye might be applied: 
cream takes well afterwards. 

Enlarging a Quantity of Small Photographs.— 
To enlarge to cabirjct size, with as little expense as 
possible, a consideiiible number of small photographs, 
starap^ size, the priTits must be copied the same 
size, and the negatives thus obtiiinod enlarged upon 
bromide paper. It llie prints are uumounted, proceed 
as follows :— Soak them in water, and, while they are 
still in the water, get as many as can be accommodated 



exceeds 60 ft. vertical height, and at this height it 
is seldom tha,t the water is anywhere near boiling 
point in every part of the apparatus (except the cold 
supply pipe), as the 1 in 30 rule requires it to be. 
The common practice, therefore, is to let the expansion 
pipe extend at least 2 ft. above the cold-water line in 
houses of moderate size, and 3 ft. or more in tall houses. 
This is easily remembered, quite safe, and applies to aU 
systems of apparatus. The quantity of water held in the 
apparatus makes no theoretical difference. In practice, 
it may mean that the large quantity does not get so hot. 

Making Liquid Malt Extract.- To prepare a small 
quantity of liquid malt extract, cover the malt with water 
and heat to a temperature ot 180" F. for an hour, then press 
out the extract from the grains. The addition of a small 
quantity of spirit ot wine will prevent it becoming musty. 
On a large scale, the malt is thoroughly exhausted with 
sufficient water, and the liquid concentrated in a vacuum 
pan at a temperature of about 180° F. A steam heat (i.e. 
212° P.) spoils the malt extract to some extent. 

Oiling Watches and Clocks.- In choosing the oil 
to be used for watches and clocks, it should be remem- 
bered that a watch will generally go from two to three 
years before the oil dries up. A clock, as a rule, wiU go 
from three to five years, according to the situation of the 
clock and the fit ot its case. Dried-up oil must always be 
removed before applying fresh; thus a watch requires 
cleaning every two or three years. Watches require a very 
thin light oil, clocks a heavier oil ; clock oil would soon 
stop a watch, and watch oil would soon run away from 
the pivots ot a clock. 



118 



Cyclopaedia of Mechanics. 



Dimensions ol Uanoe to Carry One Person.— 

A canvaa canoe of the following dimensions would 
oai-ry one person of ordinary weight on about 4i-in. 
draught, but by adding 2 ft. to her length she would be 
considerably easier to propel :— Length over all, 10 ft. 6 in.j 
length on load water-line, 10 ft. ; beam at gun wale, 25 in. ; 
beam on load water-line, 27 in. ; di'aught amidships, 4i In. ; 
draught at ends, 3iin. ; freeboard amidships, 4in.; free- 
board at ends, 7 in. ; the greatest beam being on load 
water-line, and at a distance of 6 ft. from the bow. Oak, 
rock elm, pine, or larch will be suitable for the canoe. 

Determining Contents of Cylindrical Tank. — 

First determine the contents of the tank in cubic 
feet. To do this, square the diameter in feet and 
multiply by 7854 ; then multiply by the length in feet. 
Thus the contents of a circular tank 7 ft. in diameter 
by 18 ft. high will be 7 x 7 x -7854 x 18 = 38-5 x 18 = 
693 cub. ft. (approx.). Then 6'23 gal. of water occupy 
1 cub. ft., BO that the contents of the tank wlU be 
about 693 x 6-23 = 4,317 gal. A quicker way is to reckon 
that a tank Itt. in diameter and 1ft. high will hold 
4'9 gal. Then, since the capacity will vary with the 
sqxiare of the diameter and with the length of the 
tank, it will be about 4-9 x 7 x 7 x 18 = 4,320 gal. 

Shaping the Top Kali of Greenhouse.— To deter- 
mine the bevel or slant of the top cross-bar so that the 




centi-e, with gold incised borders and corners. To elld 
these, it is usual to finish polishing the panels before 
passing on to the gilder, who will brush into the 
incisions several coats of parchment size and whiting 
tintod with orange or lemon chrome ; this mixture must 
be spread evenly, as It sets very quickly. Clean off the 
surplus with a slightly wet rag stretched over a flat cork 
rubber ; avoid rubbing any more in the channels. When 
a solid basis has been thus formed, oil gold size is 
applied bymeans of a very fine hog-hairbrush ; it is spread 
evenly. W hen nearly dry, it is ready for the gold leaf, 
which is out up into narrow strips on a special cushion ; 
this is laid over the lines, and well skewed in by a tuft 
of wadding and camel-hair brush. Clean off all surplus 
as before, using a piece of cloth slightly damp with 
turps. 

Pattern for Square Aquarium Top. — To make 
a perforated square zinc top for an aquarium, that 
could be taken off and put on as required, com- 
mence by drawing a plan and elevation (Figs. 1 
and 2) to the required size. Divide the semicircle d d 
(Fig. 2) into six equal parts, and draw lines at right 
angles to C to pass through the division points b b ; also 
join the division point c to and <J to C. Fro tn any point 
along X T erect the perpendicular O o, and from mark 
off lengths corresppnding to b B, c C, d (Fig. 2) ; join 
these points to o, and the lengths found, B o, C o, D o, will 
be the true slants of the lines 6 B, c 0, (J (Fig. 2). To 
work the pattern, draw a straight line equal in length to 
C (Fig. 2) ; mark upon this line a centre point A (Fig. 3), 



Fig 3 I 

Shaping the Top Kail of Greenhouse. 

piece shown in Fig. 1 shall be fitted as in Fi^. 2, draw 
(Fig. 3) to scale as shown. Along a horizontal line mark 
off the span of the greenhouse to 1 in. to the foot say, as 
indicated by A j then draw the vertical line shown at B, 
and mark off the amount of fall (that is the difference 
between the height of the front and back) to the same 
scale. Then the line represents the correct fall. The 
end view of the rail can now be marked out full size 
as shown at DEI', and the triangular piece scored 
shows the amount of material to be taken off. A gauge 
may be set to the distance G H, and the wood marked by 
it ; or a bevel can be set as indicated by the dotted lines, 
and the wood planed to suit it in the ordinary manner. 

Bow to Gild Piano Fronts.— Artistic designs similar to 
work seen on piano panels are usually put on by transfer 
process after the panels have been boaled up ; the sub- 
sequent polishing and finishing out will give an appear- 
ance of lulaid brass. In exceptional cases the panels 
are lluished out first, the decorative design is carefully 
cut in with oil gold size, the gold applied, and afterwards 
outliucd and shaded with sienna. Occasionally engraved 
patterns may be seen, but in the majority of cases only 
the outlined portions are gilt, the lines being very fine. 
Piano fronts are often finished with a marqueterie 




Pattern for Aquarium Top. 

and mark on either side of A divisipns corresponding to 
A B (Fig. 2) . From A, B, B (Fig. 3) draw lines at right angles 
to C C, and mark on these lines from the point A, a length 
equal to D' A' (Fig. 1) , and from B, B lengths equal to o B 
(Fig. 1). Next use as centre, and with radius o (Fig. 1) 
draw an arc ; with b o (Fig. 2) as radius and 6 (Fig. 3) as 
centre, cut the arc first drawn to obtain the point o ,- again 
use c as centre on both sides lof the pattern, and with 
radius o D (Fig. 1) draw an arc ; with the division length 
c & (Fig. 2) out the arc so as to obtain the point d. Now 
take the length o D (Fig. 2) as radius, and again using 
(Fig. 3) as centre, draw an arc \ with D' d! (Fig. 1) as 
radius and d on the pattern as centre, cut the arc first 
drawn. Join the intersecting arcs dD by a straight line, 
and also join D 0. Draw a curve through the intersecting 
arcs d,a,i,a,b,c, d,to complete the half pattern with seams 
placed in the centre of the sides at D d, D d. Then 
making the top, bend the corners upon any sharp- 
edged tools until the sides form a right angle with the 
end ; the semicircle forming the half top can be brought 
to shape by pressing the perforation to a circular shape 
with the thumb. If the two halves are to be grooved 
together, an equal allowance for the groove will be 
necessary on each side of the pattern; if soldering 
is adopted, then one lap, as shown, will do. 



Cyclopaedia of Mechanics. 



119 



Grease for Under-carrlage of Victoria.— The best 
lubricant to use on the perch bolt and felloe pieces when 
putting together the under-carriage of a victoria is 
made by melting some tallow, then mixing with it 
sufficient axle oil so that it will be quite soft when cold, 
and about two small packets of powdered blaoklead 
to lib. ot tallow and oil. The under-carriage, it the 
Tehicle is in constant use, should be taken out each time 
the trap is oiled, which is about every three months. 

Removing Brass Collars from Glass Ware.— 

If it is wished to preserve the collars, allow them to 
stand for some time in dilute hydrochloric acid, which 
will dissolve out the plaster-of-Paris. If the collars are not 
required, place them in strong nitric acid, which will 
dissolve the brass. Another method is to make file marks 
just above the collars, heat a piece ot glass rod or thick 
iron wire in the blowpipe flame, and place it on the file 
marks. Often a crack will go right round at once ; if 
not, the crack can usually be obtained after two or three 
heatings in this way. 

Tightening up Floor Boards without Using a 

"Dog." -Floor boards can be tightened up without the 
aid of a floor dog by the method shown at Fig. 1. 
The board next the wall should be well secured to 
the joists, and then three or four boards can be laid 
flown and tightened up by means of wedges, as shown. 
The following is the method of procedure :— Place a piece 




leather or felt and sprinkled with rouge of increasing 
degrees of fineness. If revolving tables are used, the 
glass plate must be fixed in a frame capable of being 
adjusted at any required angle, and the frame must be 
brought down until the edge ot the glass just touches 
the table. As the grinding proceeds, the glass is brought 
lower until the bevel is fully formed. After bevelling 
, all the edges the glass must be transferred to the smooth- 
iug table, and finally polished on the wood table. It 
fixed tables are used, the frame containing the glass 
plate wiU have to travel perfectly true backwards and 
forwards over the tables. 

Taking Apart a Geneva Lever Watch.— In taking a 
Geneva lever watch apart, first remove it from its case ; 
then lever off the hands, remove the dial, and take off 
the motion wheels underneath it. Next remove the 
central set-hand arbor by knocking it out with a light 
tap. It is friction-tight only in both the cannon pinion 
and the centre wheel. Then let down the mainspring by 
a key on the winding square while holding the click 
back. Take out the balance, pallets, 'scape wheel, train 
wheels, centre wheel, and barrel in the order named. 

Particulars of Sallnometers.— There are two kinds, 
one giving the percentage of common salt in the solution, 
the other used by marine engineers as a guide to the point 
at which to blow off. Sallnometers are made either of 
glass orbi-ass in the form shown in the adjoining figure. 
On the 'first kind each mark represents 1 per cent, of 



Fig. 2 
Tightening-up Floor Boards. 

of quartering about 2 in. by Sin. next to the floor board, 
as at 0. Gut a wedge, and place it as at £ ; then nail 
down a piece of batten to tne joists, as at A (both this 
and the wedge can be cut out of odd pieces of fioor 
board). The wedge B should be driven with a large 
hammer or axe until the joints of the board are quite 
close. Use prepared grooved and tongued boards, a 
section of which is shown at Fig. 2, to prevent dust and 
draught passing through the joints of the boards after 
they have shrunk. 

Transferring Drawings to Linen.— Transfer draw- 
ings of flowers, etc., are made with some composition 
on tissue or tracing paper from stencil plates out to 
suit the particular patterns. The composition is a 
material consisting ot resin and colouring matter 
(common red sealing wax would do). This is powdered 
and sprinkled over the stencU. while it is lying on the 

Saper. On running a hot iron over the stencil plate the 
esign is left on the paper. To transfer to linen, place 
the paper on the linen and run a hot iron over the back 
of the paper. 

Blackening Brass Buttons.— To mf ke shiny brass 
buttons black, immerse them in a strong solution ot 
copper nitrate or sulphate. Then heat them on a hot 
plate or carefully in the flame ofaBunsen burner till they 
are black. Well swill them in hot water, and dry out in 
sawdust ; polish with a blacklead brush and lacquer. 

Bevelling Plate Glass.— To obtain a bevel edge on 
plate glass, either circular revolving tables or fixed ones 
may be used. The table for grinding is of thick cast iron, 
and is fed with sand and water ; the smoothing table is 
of glass with emery of different degrees of fineness and 
water, and the polishing tables are of wood covered with 




Salinometer. 

common salt ; on the second kind there are only three 
or four marks, one being marked " blow." To use the 
instrument, fioat the salinometer in a little ot the water ; 
the mark on the stem corresponding with the surface of 
the water indicates the density of the liquid. 

Mixing Lime Concrete.— For ordinai-y fouudationR, 
with.no great or concentrated loads, the following pi'o- 
portions may be adopted : Bricks, broken to pass through 
a 2-in. ring, ii parts ; clean, sharp sand, 2J parts ; ground 
lias lime, 1 part. If the bricks are broken to pass through 
a li-in. ring, then 5 parts to 2 parts sand and 1 part lime 
may be used. The materials should be accurately 
measured in gauge boxes, turned over twice or thrice, 
dry, so as to be intimately mixed before being wetted, 
water applied by means of a watering can with a rose on 
the spout, materials again turned over twice, deposited in 
the required spot in layers about 12 in. thick, carefully 
rammed, and left to set. It is important not to disturb 
the mass after it has begun to set. 

Cleaning Velvet -pile T4ble Cover.— To clean a 
velvet-pile table cover, first remove all dust by hanging 
up the table cover and carefully beating it ; then treat 
it several times with benzine, pressing each time so as 
to remove all the dirty liquid; then hang it in the 
open air to dry. Of course, this dry cleaning should 
be done in a room in which there is neither fire nor 
artificial light. After thoroughly drying, if the table 
cover is not sufficiently clean, lay it on a table and 
carefully sponge it all over with a mixture of equal 
quantities of methylated spirit and water. Do not wet 
it more than is absolutely necessary, and immediately 
dry it hy pressing dry , clean linen cloths upon it. Again 
dry the cover, and brush it carefully with a moderately 
stiff brush to raise the pile. 



120 



Cyclopaedia of Mechanics. 



Heat-resisting Covering for Steam Boilers.— 

Hair, cotton, fibres of organic origin, and feathers ai'e 
the hest materials, though fine sawdust and corli powder 
have been used. Clay with fibres, and fibres with cow- 
dung have also been employed. The materials should 
first be powdered, and afterwards applied In the form of 
washes to the surface, which must be quite free from 
grease. A covering of canvas, wire netting, hoop iron, 
hoards, etc., should be placed outside. 

Making a Pedestal for a Table.— The following 
illustrations give a design for a pedestal for a walnut 
table top ; the table is 2 ft. diameter and i in. thick. 
Pig. 1 shows the elevation and Fig. 2 the greater 
part of the plan, looking up. The column should be 
turned out of stuff about 3in. square. The upper part of 
the column can be finished with a screw, as shown at 
Pig. i, for fastening on the block. The legs should be 



with a damper, and holes in the roof for stoking purposes. 
In starting the kiln all the compartments but one are 
filled with limestone loosely piled and the doors made 
up. Fires are made in the empty compartment, and the 
dampers are all closed with the exception of that in the 
farthest chamber, so that the fiames and hot air have 
to travel all round the kiln before they escape to the 
chimney. As the coal burns away slack is fed through 
the holes in the I'oof, and when the limestone is fufly 
burnt in the first compartment the damper in the empty 
compartment is thrown open and the other closed, so 
that the empty compartment becomes the last in the 
series, and thfe first compartment begins to cool down. 
The coal is now fed through the roof of the second com- 
partment, and this procedure goes on right round the 
kiln. The empty compartment is charged as soon as It 
is cool enough to enter; the first compartmentls next 
emptied and refilled, and so on, emptying and refilling 





cut out of material with the grain running in the direc- 
tion of A A (Fig. 1). A simple method of connecting the 
legs to the column is by means of dovetail housing, 
shown at Fig. 2. A conventional view of this joint is 
shown at Fig. 3. It should be noticed that the shoulders 
require to be undercut (see B, Fig. 3). The "drop" 
shown at C (Pig. 1) is a separate piece of turning with a 
dowel attached so that it can be fastened to the bottom 
of the column. The top may be hinged to the block by 
means of two flaps, as Indicated at Fig. 4. 

Method of Burning Limestone.— No very great 
improvements in the method of burning mountain 
limestone have been made for several years, but 
there are kilns, such as the Hofmann kiln, and 
calciners which are great improvements on the old 
forms of kiln. The Hofmann kilns are very large 
and circular or oval surrounding a chimney stack) 
they can be divided into twelve or more compartments, 
each one of which has a door for charging purposes, an 
opening connecting it with the chimney and covered 



How to Make a Pedestal for a 
Table. 



going on all the time. The caloiner is made in the usual 
form of circular kiln, but it has a cone-shaped structure 
at the bottom, and there are openings all round the 
circumference of the furnace above the floor level. The 
limestone and slack are fed in at the top, and as the coal 
burns away and the limestone contracts during its con- 
version into lime, it gradually descends, but is prevented 
settling at the hottom of the furnace by the cone- 
shaped structure, which directs the material towards 
the walls of the furnace, and it falls out through the 
openings above mentioned. 

How to Get Rid of Mites In Furniture.— 

Use ordinary furniture polish on the wood of the 
furniture, and place a saucer full of strong ammonia 
below the sofa and chairs from time to time. As a rule, 
a dry room is best for furniture, and therefore a fire 
should be lighted often. It will prevent the- damp 
settling upon the furniture and carpets, and will tend tui 
keep out insects. Washing the floors with a carbolic 
soap will also be found of great v.alue. 



Cyclopaedia of Mechanics. 



121 



Varnishing a Van In the Natural Wood. — 

Where the grain is to show out plain it is not custom- 
ary to stain the wood; staining hlurs the natural 
grain, on account of one part absoroing more stain than 
another. The method usually adopted for vans, etc., is 
as follows : After the hody is got up clean, and glass- 
paper marks across the panels hays been removed, 
apply a good coat of pale gold size, to which about a 
tablespoouful of linseed oil to a pint of size has been 
added ; let this stand a day or two, then lightly rub over 
with flue sand or glasspaper to take oft the grain which 
will rise ; then give another coat of gold size only. "When 
hard, sandpaper off as before, and apply a coat of hard 
drying carriage varHish. Let this stand for a couple of 
days, and then flat down with ground pumice-stone and 
water, being careful to wash every particle of dust from 
the corners ; then give a coat (or two coats If necessary) 
of best carriage varnish. 

Enlarging with Fixed Focus Hand Camera.— 

The accompanying sketch shows an arrangement for 
making either enlarged negatives or prints. In the 
bottom of a lidless box M cut an opening 41 in. by 3Jin. ; 
fit grooves A A top and bottom, to carry the negative B 
(the box is standing on end) . make a box B of the size 
and shape shown (see also ground plan), having an 
opening at P a little smaller than the hand camera H, 
and with a close-fitting fillet run round it on the outer 
Bide at 1, forming a recess, into which the back of the 



frame. The above dimensions are worked out on the 
assumption that the lens is of 5-in. focus. 

Using Gold Bronze. — To apply gold bronze to 
furniture in paint form, coat the furniture with 
paint, japati, spirit varnish, or anything that will 
prevent suction ; then coat where the bronze is wanted 
with gold size or quick-drying varnish. When this is 
nearly dry, dust on the powder with a camel-hair brush 
or soft new chamois leather. As bi-onze is susceptible to 
atmospheric influences, it should be coated with a thin, 
even coat of varnish— clear spirit or oil varnish will do. 
Work thus treated will have a common brassy appear- 
ance, by no means egual to gilding. When gold leaf is 
too expensive, use Dutch metal, which can be purchased 
at from 2d. to 6d. per book. 

Moulding and Vulcanising Indlarubber. — The 
tooljS required would be a small rotary cutter, a sheet- 
iron box with sliding fronb and chimney at top, 
an iron tray, two large ring gas burners, knives or 
spatulas, and iron moulds shaped like the blocks 
rejiuired. The rubber may be out in the rotary machine, 
mixed with powdered sulphur, placed on the iron tray in 
the sheet-iron box, and heated by the burners. A 
tiio^mometer hung in the box very close to the iron 
tray will show the temperature, which must not rise 
above 300" P. When the rubber is softened, the moulds 
may be heated in the box, the rubber put in, and the 
tops of the moulds forced down so as to compress the 




Enlarging^ with Fixed Focus Hand Camera. 



camera fits, and is supported on the bracket E. The 
bracket is either detachable or hinged at O. At the 
rear of the box is fastened another fillet P, at exactly 
13 in. from the lens stops. Out a slot right down one 
Bide rather greater in vridth than the thickness of a 
whole-plate printing frame. The frame should now be 
built up at the same side flush with the outside of the 
box, and a further piece screwed on, projecting iin. each 
way beyond the opening, and fitting close to exclude 
light. Now insert the frame, facing the lens, and ^orew 
another fillet behind it, so that it just runs easily 
between them. The frame is assumed to measure lOi in. 
bySJin. Next cut from a block of wood C a recess to 
form a bed for the condenser N, the centre of which 
must be exactly opposite the centre of the negative, the 
lens, and the printing frame. A lid may be hinged to D. 
The ca"mera and other loose parts may then be stored 
inside. Now construct a board 36 in. by 8 in., hinged in 
the centre. Put two screws in the extreme end ; these, 
by engaging with holes in D, ensure its being always in 
the same place. Now place the other parts roughly in 
position. Fix, with drawing-pins at the corners, the sheet 
of ground glass, rough side outwards, in the printing 
frame, and insert it in D. Having put the negative B in 
position, focus very accurately by moving the box.to and 
fro. The condenser and light are next manipulated 
until the corners of the negative are illuminated and an 
evenly lighted screen is obtained. Then screw the 
block in position in M, and fit the points for the other 
parts as before. Instead of using a condenser, a piece 
of magnesium wire may be burnt behind the negative, 
the light being waved about, so that the negative may be 
evenly illuminated. In this case a sheet of ground glass 
should be placed a few inches behind the negative. To 
use the apparatus it will merely be necessary to insert 
the negative, then place in the printing frame a sheet of 
clear glass, free from bubbles or scratches, and of the 
same thickness as the ground glass mentioned above. 
Place upon this, face downwards or outwards, a sheet of 
bromide paper, and, having turned the light down very- 
low, insert through K. If preferred, a sheet of card- 
board, which can be slid out after placing the frame m 
position, may be made to run in front of the printing 



rubber; the moulds may then be allowed to become 
cold, and t'le blocks withdrawn. Before pressing in 
the rubber, rub powdered French chalk over the insides 
of the moulds. 

Obliterating an Engraved Crest on a Silver Jug. 
—To remove an engraved crest from a small silver jug, 
(1) file out the work with a fine flat file if the 
surface of the jug is of a full or rounded nature, and 
with a rifller or small bent file if hollow. Finish with 
snakestone or Tamo'-Shanter hone, and polish with 
rottenstone and oil. Send it to be electro-gilded and 
scratch-brushed on the inside, with a light coating of 
silver on the outside, and have the outside burnished 
and " handed up." The jug will thus look equal to new. 
Before sending to plate, look well over for possible 
dents. (2) Fill up the cuts with silver solder— same 
colour as near as possible to the silver— dress off, and 
finish as No. 1. (3) Cut out a shield from sheet silver 
(No. 6 to 9 gauge, §.M.G.) either round, oval, or of an 
heraldic shape, hard solder neatly, and finish as No. 1. 

Shaping Soap into Bars and Tablets:— The soap is 
made by boiling fats and caustic soda in large pans, from 
which it is run through channels over the " frames " ; the 
latter are large rectangular moulds built up of iron plates 
bolted together. When the soap is cold the plates are un- 
bolted and removed, revealing the blocks of soap. A frame 
with horizontal wires is run through the blocks, cutting 
them into slabs. The slabs are pushed against other 
wires, cutting them into bars. Tablet soaps are pressed 
from the bars or from ribbons. Toilet soaps are made 
by forcing bar soap against a cutter, which cuts it into 
thin slices; the slices are placed in a roller machine, 
from which it emerges in the form of extremely fine 
shavings. The shavings are partly dried on wire netting 
in a heated room and then placed in a press, from which 
the soap emerges as a bar with a square, round, oval, or 
other section. The bar is cut into pieces of equal thick- 
ness forming plain tablets, which are then pressed in a 
machine having dies with appropriate designs. In 
scented soaps the ribbons are gently heated with the 
scent, or the scent is added immediately after the soap 
is made for common qualities. 



122 



Cyclopaedia of Mechanics. 



Calculating Heating Surface of Radiators.— For 

calculating the heating surfaces of radiators and pipes 
for schools, greenhouses, etc., the following notes are use- 
ful :— For brick buildings, for a temperature of 60° P., use 
7 sq. ft. of heating sui-faoe for every 1,000 cub. ft. of 
space ; for 55° F., use 9 sq. ftj for 60°F., use 12 sq. ft. j for 
65°F.,use 15sq.ft.; tor70°P.,UBe lOsq. ft. For lean-to 
glasshouses, for a temperature of 46° F., use 37ft. of 4-in. 
pipe for every 1,000 cub. ft. of space; for eO*F.,nse40ft. 
of 4-in. pipe; tor 65° P., use 45ft. of 4-ln. plpei for 60° P., 
use 60ft. of 4-in. pipe; for 65' P., use 65ft. of 4!-ln. pipe; 
and for 70° P., use 60ft. of 4cin. pipe. For span houses, 
add one-fifth. 

How to Find tbe Mitre, etc., of Raking Cornice 
Moulding.— A (Fig. 1) shows the true section of the 
raking moulding. The five points have been taken In the 



A cheap clock with a light pendulum should have an 
escapement with a moderate recoil only, and a good 
clock with a heavy pendulum should have a nearly 
dead-beat escapement, or what is known as a "half 
dead," i.e. a dead-beat with a very slight amount of 
recoil on the resting surfaces, but hardly perceptible 
The amount of recoil is deteriuined by the shape of 
the pallets. 

' Making Marlboro' Easy Clialr.— Figs. 1 and 2 show 
front and side views respectively of the framing. 
The total height is^^ft. ; width, lift.; height of Bent 
without cushion, 1ft. lin.; height of arms from seat, 
1 ft. ; and width of seat from front to back, 1 ft. 8 In. 
The back legs, with the required sweep at the bottom, 
can be bought ready sawn at any chairmaker's. The 
seat frame is made from 2-ln. by U-in. stuff; the 
rest of the frame from 1-in. stuff, with the exception 
of the front legs, which can be made Chippendale 
shape, square tapered, or turned in the lathe. Web 
the seat, back, and arm space tor foundation for stuffing. 




How to find the Mitre, etc., of Baking Cornice Moulding. 

curve, and lines 6, 7, 8, 9, and 10 drawn through them. 
Then from these points perpendiculars are drawn to the 
bottom line— Nos. 1, 2, 3, 4, and 6 ; also C. From E draw 
the vertical line a' E, and at right angles to it a' c'. Now 
mark off the divisions a', V, 1, 2, 3, 4, 6, and c' as shown, 
making them correspond to a, b, etc. Next raise 
ordlnates, making them intersect their respective 
raking line as shown. Through these points draw the 
curve, and complete the section of the level moulding. 
To obtain the mitre, project the plan as shown at Fig. 2 ; 
then take the distance E F (Fig. 1) and mark it off on the 

5 Ian as shown at E' I" ; pro.iect across to G, and join P' to G. 
'hen the bevel for the mitre of the raking mould will be 
that shown at L, and that at K for the bevel mould. 

Clock Escapements and Motive Power.- When 
a cheap clock, such as an American spring clock 
without a fusee, is first wound up, the motive power 
is very great, and when the same clock is nearly 
run down, the power has diminished to perhaps less than 
halt. The effect of this with a recoil escapement (one in 
which the 'scape-wheel recoils at each beat) and a 
light pendulum is to make the clock go gradually slower 
as it runs down. With a heavy pendulum the error is 
less. A dead-beat escapement (one in which the 'scape- 
wheel remains perfectly still between each beat) has a 
very small error in the opposite direction, and the same 
clock fitted with it would gradually gain as it ran down. 
Therefore, to keep correct time, the escapement must 
not nave mueh recoil, nor must It be perfectly "dead." 



Marlboro' Easy Chair. 

Make a loose cushion seat. Upholster in coarse canvas 
with hair or fiocks, nailing the material on the outside 
edges ; then cover with Gobelin tapestry or cretonne ; 
cover the sides and back with the same material, sewn 
together at the edges and corded, or tack round a 
narrow coloured gimp. 

Colouring Drawings.— The colours used in architec- 
tural and mechanical drawings vary according to circum- 
stances. Some draughtsmen use a very pale sepia for York 
stone in elevation, pale Payne's grey for Portland or 
Bath stone, pale indigo with ink dots tor' granite, and 
darker tints of the same colours for the sections. This, 
it must be remembered, is chiefly in connection with 
London stock bricks. Architects, who ought as a body 
to have an eye for colour, are sometimes great offenders 
by using harsh and unnecessary colours on their 
drawings. An extreme case has been noted where a 
wrought-iron girder resting upon a cast-iron column 
standing on a stone base were all coloured bright 
Prussian blue. Blue in some form or other is much used 
by architects to represent stone, but it should be used 
very sparingly, so as to resemble the natural tint of the 
stone rather than the conventional representation. For 
a red sandstone, a pale tint of light red, Indian red, 
Venetian red, or burnt ochre might be used, dependmg 
upon the general elevation colour. For cement in any 
form in elevations, pale Indian ink or pale Payne's grey 
is generally used, with or without dots and markings. 
Windows may be coloured with black Indian ink, or 
washed Prussian blue, Prussian green, or Payne's grey, 
according to circumstances. A plain tint all over is the 
simplest, but a good artistic effect may be obtained with 
the exercise of a little skill. 



CycTopaedia of Mechanics. 



123 



Oleomargarine — This is the softer portion of the 

fureet and freshest beef suet from the ribs, rendered at 
40* P. to 150" P., and the fat poured off clean and pressed 
at 95* F. The product is of a buttery consistency at 
ordinary temperature. The " oleo " oil, as it is called, is 
the chief constituent in margarine, bat a vegetable oil 
is also employed ; sometimes this is cottonseed oil, at 
others earth-nut oil or sesame oil. The oleo oil is 
melted and, along with the vegetable 'oil, is run into the 
churns ; the milk is first soured by the addition of acid, 
rennet, or sour mUk, run over cooling coils, and then 
into the churn. The churns are kept slightly warm, and 
are worked so that the fat, casein, etc., may amalgamate. 
They are then emptied into tanks containing water cooled 
with ice, the masses of fat are removed, piled up to drain 
for some time, then worked and salted like butter. 

Bamboo Newspaper Rack. — Four 1-in. and two 
l-In. canes will be required ; from the former 
four lengths should be bent or toed out tlnd cut off 
20 in. long. Pour pieces, each 16 in. long, for the four 
rails should now be cut off from the 1-ln. canes, 
chisel-pointed, mortised (or hollowed) with the rasp, and 
fitted in their places. Holes should then be bored in the 
legs to receive the dowels, and the two sides framed up. 
While these sides, or sections, are setting, the two 
ornamental fillings should be made from f-in. cane. 




Bamboo Newspaper Rack. 

Pour pieces of 1-in. bamboo, each 9 in. long (IHn. is 
allowed for fitting), should now be prepared to form the 
cross rails which are to join the two sections together. 
When the sections are set, holes should be bored to 
receive the dowels of the cross rails, and the whole 
joined together. The two uprights for the partition 
are fitted to the bottom cross rail, and the top cross rail 
and upright are half jointed where they cross. The rail 
which carries the handle is mortised and dowelled at 
each end and fastened into position with two round- 
headed screws. The handle is made frgm f-in. cane bent 
as shown, and fastened to the centre rail with round- 
headed screws. The raUs which form the division of the 
partition, as also the three cross rails forming the 
bottom, are made from J-in. cane mortised at the ends 
and fixed into position with beading pins. A diagonal 
stay, not shown in the illustration, may be added to the 
central framework. 

Ftaotograpliing an Oil Painting. — Whether the 
painting is under glass or not, it will probably he 
advisable to let it face the window. All refieotions 
must he got rid of; sometimes slightly tilting the 
picture and swinging the back of the camera to 
compensate for it will be effectual. If possible, the 
centre of the lens should he opposite the centre of the 
painting. If the illumination in the camera is weak, 
f ocuB upon finely grained glass, made by thickly coating 
a sheet of glass with negative varnish, and then rubbing 
down the surface with a little finely powdered resin on 
the ball of the finger ; or the • ordinary ground glass 
screen may be oiled. A firmly fixed copying camera, in 
which focussing is done by moving the back part, would 
be preferable to an ordinary camera. The lens should 
he one giving a flat field and the best possible definition. 
The stand must be rigid, and, as the exposure is pro- 
longed, every precaution must be taken against vibra- 
tion. The plates used must be colour - sensitive ; 
Edwards' instantaneous isoohromatic are very suitable. 
If the picture contains any blues or greens, a yellow 
screen must be used— a home-made substitute for which 
can be made by staining to a lemon yellow a fixed 



unexposed plate in a weak solution of picric acid. If the 
stain is too deep, the blues and greens will be rendered 
too dark. Pyro soda is a most satisfactory developer for 
the above-named plates. Use equal parts of each of the 
following solutions :— No. 1. Pyro, 25gr.i sodium sul- 
phite, 4oz. ; water, 5oz. ITo. 2. Washing soda, 165gr. j 
water, 5 oz. Add one drop per oz. of 10 per cent, potassium 
bromide solution. The negative should be thin and full 
of detail, with clear shadows. 

Vienna Regulator Striking Clock.— In the accom- 
panying figure the wheels between the plates are 
represented by plain circles to show their positions. 
The gut lines are wound up on barrels, fitted with 
winding ratchets and clicks and click springs to prevent 
running back. The main wheels are driven by the 
barrels, and are mounted upon the barrel arbors. 
Around the pin wheel are arranged the lifting pins, 
which lift the gong hammer. The pallet wheel arbor 
carries the gathering pallet, which gathers up the rack 
teeth during striking. The snail, mounted upon the 
star wheel, determines the number of blows to be struck 
at each hour. This system of wheels is known as the 
rack striking work, and is used in a great many Prench 
clocks and in nearly all English grandfather and bracket 
clocks. The letter references are as follows :— A is the 
striking main wheel, B pin wheel, pallet wheel, D 
warning wheel, E fly, P going main wheel, G minute 
wheels, H centre wheel, I third wheel, J 'scape wheel, K 
pallets, L minute wheel cock, M warning lever, N lifting 




Vienna Regulator Striking Movement. 

piece of warning lever, O rack hook, P gathering pallet, 
Q rack, £ star wheel and snail, S flirt, and T the flirt 
spring. 

How to Make Crystoleum Photographs.- A portrait 
should be chosen giving good gradation without very 
deep blacks. A pair of concave glasses in different sizes 
may be bought of any artists' colourman, and should 
be chosen to fit the picture. Mix some starch— as for 
ordinary mounting— to the consistency of thick treacle, 
fre? from lumps, and, having carefully cleaned the 
glasses and soaked the print and blotted off the surface 
moisture whilst lying face up on a sheet of glass, brush 
the starch well over the face of the print and over the 
concave side of the glass. Bring the two surfaces into 
contact and lay over the picture a thin sheet of blotting- 
paper ; place the glass on a cushion and work the print 
thoroughly into contact with the glass by stroking with 
the convex side of a spoon in all directions from the 
centre until all air bubbles are expelled. When the 
print thus mounted is thoroughly dry, it is rendered as 
transparent as possible by rubbing away the paper, 
quite evenly, with fine glasspaper. When the film is 
nearly reached, cuttlefish powder may be applied with 
the finger or a tuft of wool. The print is next warmed 
carefully and rubbed over evenly with castor oil till it 
wUl take up no more, the surplus oil being wiped off and 
the print allowed to cool. Transparent oil colours are 
next laid on over the dress, hair, eyes, lips, etc. Plat 
tints merely are used, as the transparency supplies the 
modelling. The second glass is then attached, and on it 
the flesh tints are painted. The outlines must in all 
cases be carefully followed. The crystoleum may now 
be bound up by placing a piece of white cardboard at 
the back and binding the edges with black paper. 

Stain and Varnls^ for Elm.— For Indoor work, use 
a good quality spirit varnish i for outdoor work, use a 
good oak, copal, or carriage varnish. A wipe over with 
raw linseed oil will fetch out the figure, a reddish tinge 
being imparted by colouring the oil by adding a small 
quantity of alkanet root— 2oz. to Ipt. Elm is a good 
wood for taking a walnut stain. Use a grain filler before 
applying any varnish or polish. 



124 



Cyclopaedia of Mechanics. 



Two Boilers to One Hot-water Cyltndor.— When a 

cylinder system apparatus is to be heated by two boilers, 
one boiler is generally connected to the cylinder in the 
usual way, and the pipes from the second boiler con- 
nected to the pipes of the first one, flow to flow and 
return to return. No fault can be found with this 
arrangement, which works well, whether either boiler is 
used separately or both are used together, and no stop- 
cocks are needed. However, a better arrangement is 
to connect the pipes from each boiler into the cylinder 
independently, instead of allowing the pipes to join out- 
side the cylinder. In this ease there is the possibility 
of more uniform results, and it seems a more correct 
way to do the work, although no fault can be found with 
the plan first explained. 

Construction of Tenons for Entrance Gates.~The 

construction of tenons for gates, such as entrance gates 
to parks or lodges, is shown by portions of two typical 



upon it like water. Now press the tip of one finger hara 
upon it and wipe the finger again immediately. It 15-ct., 
the spot will turn a pale brown, as 9-ct. did before 
pressing with the finger. If 18-ot. or over, the acid will 
still stand upon it like water ; 22-ct. can be told by its 
colour by an expert. 

Dry-oleantng a Valencia Waistcoat. — Sprinkle 
a mixture of fuller's earth and magnesia over the 
waistcoat, then rub it in with a clean piece of flannel. 
With another piece of flannel apply benzine to 
the waistcoat, after which sprinkle some more of the 
powder and leave it for several minutes. Then brush oft 
the powder and hang the waistcoat in a current of fresh 
air till the benzine has evaporated. 

Staining White Wood Teak Colour.— Brush over 
the article some raw sienna ground in water, mixed 
in stale beer, and allow it to soak in. When nearly 
dry, wipe ofE the surplus with clean rag ; this will give 




Construction of Tenons for Entrance Gates. 



examples of gates (Figs. 1 and 5). The forms of the 
tenons, etc., are indicated by dotted lines. Figs. 2, 3, 
and i show isometric views to a larger scale of the 
tenons indicated at Pig. I. Fig. 6 is an oblique pro- 
jection of the joints at A (Fig. 6). When the rails are 
Siin. and under, they usually have tenons the whole 
width; but when over 3iin. and up to 6 in. the tenons 
are diminished generally to 3 in. or 3iin., having a 
haunch on one or both sides. When the rails are more 
than 6 in. wide, they frequently have two tenons in 
breadth as illustrated. The tenons are wedged into the 
mortises (see Figs, land 5), and as an additional Security 
they are occasionally pinned as indicated at Fig. 5. 

How to Test Gold.— Pile a clean spot upon the metal 
to be tested, so that any gilding or outside colouring 
may be removed. Apply a small drop of pure nitric 
acid to this spot, and watch it closely. It the metal 
is brass, it will boil up a bright green immediately. If an 
imitation gold alloy, it may go black in a few second* 
If 9-ct. gold, it will turn a pale brown tint. If 15-ct. or 
over, it will remain unaltei'ed. and the acid wiU stand 



a yellowish undercoat. Now take some Vandyke 
brown ground in water, mix as before, and apply, 
with a ragged piece of sponge, putting in the figure 
and varying by a tremulous motion of the hand, 
blending the colours and removing any harshness by 
going over the still moist colours with a badger softener 
or a clean soft sash tool. When quite dry, rub smooth 
with coarse rag or fine glasspaper, wipe over with rawhii- 
seed oil, then French polish or spirit varnish. A slight 
tinge of red in the polish will be an improvement. 

Producing Crystals upon Wlokorwork.— To pro- 
duce crystals upon wickerwork, such as baskets, boil 
about 2lb. of alum in 1 gal. of water, and, while still hot, 
pour this into a jar large enough to hold the baskets. 
When cool, some of the alum will crystallise out, leaving 
a saturated solution. Hang the basket in this solution,- 
tying a string to the bottom and attaching a weight, so 
that the basket is suspended in the centre of the liquid. 
If allowed to remain several day a, the basket will become 
covered with crystals, which 'will continue to grow in 
size If the jar be freely exposed to air. 



Cyclopaedia of Mechanics. 



125 



Gilding Glass.— For gilding on glass, isinglass and 
distilled water are used ; sometimes a little pure spirit 
of wine is added, iDut not necessarily, as the best results 
can be obtained -witli the distilled water and isinglass 
alone ; these must be boiled for about five minutes and 
then passed through a filter or white blotting paper. 
Three grains of the best isinglass to 6 fluid oz. of distilled 
water make a good gilding strength. The liquid Is then, 
by means of a broad camel-hair brush, floated upon the 
glass, which must be placed in a slanting position. WhUe 
still wet the gold is laid on from a gilder s tip and cushion, 
and after it has been allowed to dry It is gently rubbed 
with a pieoe of fine wadding and the cracks or joints 
touched up. A second application of the gold leaf gives 
more solidity and makes a better job. It is now burn- 
ished again with the wadding and bathed with lukewarm 
water to bring up the burnish, drying with blotting 
paper. When thoroughly di-y. burnish again, and then 
with a size brush dipped in water, with the heat in- 
creased each time, go over the gold again, thus giving 
It a third bath. It is then again rubbed and finally 
coated on the back with gilding size, which, when dry, 
is rubbed with the cotton. It is then ready for cutting 
into shape, which is done with a strip of wood out like 
a chisel. When the letters have been cut they may be 
backed with japan gold size or ordinary black japan, or 
a mixture or the two. For small ornaments such as 
corners, paint directly on the gold with the japan, and 
when thoroughly dry, rub -oft the superfluous gold to 
leave the gold figures on the glass. 

How to Make a Portifere Rod.— The rod A (Pig. 1) is 
cut from a broomstick ; at one end is fixed a fancy wood 
knob, at the other end a piece of brass pipe to act as 
a ferrule ; Into this end is screwed a round-headed brass 



4 


aM 






Fig. 1 









vanishes and the face of the marble is in some measure 
destroyed. The polishing of marble adds greatly to its 
beauty, inasmuch as its delicate figuring and gradations 
of rich colouring are brought out and heightened as it 
were by the process, which gives marble its value as a 
decorative material. With regard to the appliances, for 
mouldings the grits are cut into small strips and shaped 
into hollows and rounds to fit the various members ; and 
tor the polishing boss, an old worsted stocking, tightly 
tied up in a wad, does admirably. For plain faoework 
the grits are in flat pieces, and are used on edge, 
traversed over the face. The polishing block is a piece 
of wood from 16 in. to 18 in. long, and 4 in. wide, with a 
piece of felt on the underside fastened at each end. 

Filtration of Oils Tay Heat.— Tow, such as brewers use 
for the filtration of malt liauor, answers well as a filtering 
medium for viscous fiuids. The filtration is expedited by 
heat, and may be accomplished in the following simple 
manner. Two funnels are necessary. One tunnel is 
placed inside the other, an indiarubber plug being on 
the neck of the inner funnel, around which the outer 
tunnel fits. In order that the filtering liquid may be 
covered, the top of the inner funnel projects somewhat. 
The tow or paper is placed in the inner funnel, and the 
interspace contains water, which is kept hot by steam, 
which passes into it from a fiask. The excess of water 
may be drawn oft by means of a constant level syphon, 
or a strip of web-tape hanging over the outer funnel. 
The diagram is thus explained : — A is the outer 
funnel, which contains water, and into which steam is 
passed for heating purposes ; B, inner funnel for filter ; 
0, flask containing water ; D, flask to collect filtrate ; E, 



Fig. 2 
How to make a Fortl^re Bod. 




Filtration of Oils by Heat. 



Bcrew bent to the shape shown (B, Figs. 1 and 2). 
Before screwing this into the end of the rod, it is fitted 
Into a brass socket (see A, Fig. 2) originally made for 
door bolts to shoot in. The bracket C (Fig. 1) is made 
from J-in. iron and bent round the rod as shown, with 
one end fitted into a similar socket to that in which 
the rod fits. Brass curtain rings are put on the rod 
before it is fixed up. To fix it up, the sockets D and E 
(Fig. 1) are screwed to the door jamb. The rod is fixed 
Inside the room, and when hung with drapery it serves 
to prevent a draught blowing on to anyone sitting at 
the right-hand of door when the door is open. The rod 
could be made of bamboo and with screw-eyes in place 
of sockets. 

Polishing marble.— Marble, such as is used for mantel- 
piece jambs, is polished in a variety of ways, the choice 
depending largely upon the nature and quality of the 
material, which vary greatly. The following method 
vrill answer satisfactorily for vein, statuary, Sicilian, 
St. Anne's, Bardilla, and most of the ordinary coloured 
mai'bles in general use. The wrought surface is rubbed 
with fine sharp sand and water, until all the marks of 
chisel or saw are removed and an even surface is pro- 
duced. It is then " grounded "—that is, rubbed with grit 
stones of varying degrees of fineness, commencing with 
the coarse or first grit, usually Kobinhood stone j next 
the second grit, which is a little finer ; finishing with 
snake stone or Water of Ayr stone. Particular care must 
be taken that in each process of gritting the marks or 
scratches of the preceding one are removed, so that when 
the surface is snaked no scratches whatever are visible. 
The gloss or natural polish is obtained by rubbing with 
a pad of felt sprinkled with putty powder (calcined tin) 
moistened with water. The chief factor in this method is 
persistent and attentive rubbing, and a good polish thus 
obtained will retain its lustre for years. For speed and 
cheapness chemicals are sometimes used' for polishing, 
such as oxalic acid, hydrochloric acid (spirit of salts), and 
others, but their use is to be deprecated, as the polish soon 



glass tubing (steam from is passed along the tube to A) ; 
F, burner to heat fiask ; G, tripod stand to support fiask. 

Manufacturei of Porcelain and Sarthen ware Goods, 

— The finer qualities of earthenwai-e or porcelain goods 
are manufactured from mixtures of various clays, calcined 
bones, etc., from which every organic constituent has 
been burned out. All these ingredients are weighed, and 
mixed together in a large quantity of water, and strained 
through very fine sieves. When the clay has been 
allowed to dry till of the consistency of dough, it is 
placed by the potter on a horizontal revolving wheel, 
and the lump of clay may become a bowl, vase, or any 
other article. When the object is sufficiently dry, it is 
ready for the " biscuit " kiln, or first firing, where it is 
only partially baked. The design is then painted or 
printed on— that is, underglaze, or before the metallic 
glaze has been applied. The ware is now ready for 
dipping into glaze, literally a form of ground glass 
which the half-cooked ware, being very porous, readily 
absorbs. It then undergoes its final firing at a much 
lower temperature than that of the biscuit oven. All 
articles are placed in saggars, or receptacles of coarse 
clay, which are next packed in a kiln ; this is simply an 
oven arranged with flues in such a way as to equally dis- 
tribute the heat. The ilre is not allowed to touch either 
saggars or ware, as in the manufacture of coarser goods 
such as bricks or terra-cotta. 

Blackening and Bronzing Brass.— To obtain a 
black colour, dip the brass in a strong solution of 
copper nitrate or copper sulphate, and then heat on a 
hot plate or hold the article in a Bunsen flame. To 
bronze the metal, dissolve IJ oz. of copper sulphate 
in 1 pint of water, and pour in a solution of 1 part 
carbonate of soda in 2 parts water until the ijrecipitate 
ceases to form. Deoant, well wash the i)recipitate with 
water, and dissolve it in ammonia until the latter is 
saturated. This solution is warmed and the article 
dipped in it as before. 



126 



Cyclopaedia of Mechanics. 



Self-wlndlng Clocks.— Many hare been made. Some 
of these are being continually wound up by; means of a 
fan placed in a tall chimney shaft, up which there Is 
a natural draught that always keeps the tan revolving. 
The fan is connected to the winding shaft of the cloolc 
by suitable gearing of a speed-reducing nature. Other 
clocks are driven Toy electricity; an Impulse is given 
direct to the pendulum at each vibration by the closing 
of an electrical circuit in which is a weak battery made 
by burying carbon and zlno plates in moist earth. 
Perhaps the most noteworthy perpetual clock is in the 
British Horologlcal Institute, 36, Northampton Square, 
London, E.C. It was made more than acentury ago, and 
is dependent for its motive power on the variations in the 
density of the atmosphere. A sort of barometer con- 
taining many pounds of mercury is suspended from a 
rocking bar, and the constant shifting of the mercury 
causes the suspending bar to rock and drive the winding 
arbor by a rack and pinion. This clock has gone for 
many years, and has only been stopped to be cleaned. 

Machine for Withdrawing Axle Boxes from 

Wheels.— Pig. 1 shows the machine in position on a stock 
of a wheel ready to force the axle box back. The top 
corners are made with knuckle joints, so as to allow of side 
play to take various sizes of stocks, the top boss-piece 
being made as Fii;. 2, having good stout rivets through the 



turps is best, bound with iapan gold size; do not 
use more than loz. of gold size to lib. of colour. 
Put the colour on a piece of glass, and charge the lining 
pencil with the colour. Let the second finger rest on 
the edge of the glass as a guide ; hold the pencil between 
finger and thumb, and draw your hand towards you. If 
only a few lines are to be painted, perhaps it would be 
better to use a sign-writer's brush, and, when the lines 
are quite dry, to out them straight with a straight-edge 
and sharp chisel. Lining pencils are made from sahle 
hair, are from 2in. to 2iin. long, and are called lark, 
crow, duck, goose, and swan, swan being the largest. 

Apparatus for Washing Large Fhotographlo 

Prints.-rLarge prints are not generally washed in the 
mechanical manner adopted for small prints, because of 
the difficulty of keeping the prints from clinging 
together, and the impossibility or changing the water 
with sufficient frequency. Unless some such arrange- 
ment as described below is used, each print should be 
washed by itself. The accompanying sketches show two 
forms of washing machines for large prints. In Pig. 1 
four trays are shown placed in a rack ; each tray is in 
turn tilted to a slight angle to allow the water to run 
into the tray beneath. The trays may be of enamelled 
zinc or of wood coated with paraffin wax j they rest on 
four rails {not shown) supported by vertical posts. 




Fia 1 --V F'o 3 

Machine for Withdrawing Axle Boxes from Wheeis. 



Apparatus for Washing Large Photographic Prints. 



joints. Por ordinary work the sides should be made of 
Iron, lin. wide by Jin. thick, with a good broad duck 
foot at the bottom. The top cross-piece is made with a 
boss large enough to take a 1-in. screw ; this has a collar 
and square on the top end to take the handle shown in 
Fig. 3, the bottom end being turned down to A in. so 
as to form a shoulder for the circular bolster to rest upon. 
In use, the cramp is put on the wheel as shown in Pig. 1 ; 
the bolster, which is a trifle smaller than the outside of 
the box, is put on the end of the screw, and pressure 
applied by turning the screw down until the box, 
indicated by the dotted lines, is removed. 

Keclpes for Cheap Bed and Black Paints.- Por a 

cheap black paint for rough outside work, melt together 
equal parts of pitch and coal-tar, and thin to a working 
consistency with coal-tar naphtha. The naphtha may be 
dispensed with it the melted material is applied hot. A 
cheap red paint can be made by slaking lime with water 
and adding sufficient red oxide or Venetian red to colour 
it ; apply it as if applying whitewash. Allow it to dry, 
and tlien brush over with silicate of soda solution (Ipart 
of silicate to 4 or 6 parts of water). This paint will be 
found very durable. 

Painting Lines on a Glass Plate.- To paint narrow 
lines on a plate of glass such as is used for show signs, 
first clean the side of the glass to be lined with 
a few drops of ammonia in warm water : then polish 
with a piece of soft paper, and lay the glass flat. 
Uix the colour in turps. Dry colour ground in 



Fig. 2 shows an arrangement for washing unusually 
large prints. In this case the developing tank, 
being deep and long, may be used as a washing trough. 
The washing machine consists of two circular discs 
of wood {the ends of tubs), bored in the centre to 
receive an axle {a broomstick), at each end of whicli 
a disc is fixed, thus forming the framework of a 
skeleton cylinder, the ribs of which are laths stretch- 
ing from one disc to the other, and nailed at each end. 
Around this cylinder the print is fastened with 
wooden clips. At one end or the cylinder sufficient 
space is left for a small water-wheel, which may be 
driven by water from the tap above it. The outflow is 
regulated by a plug, thus keeping the water in the 
trough always at the same height. ' 

Making Clinical Thermometers.— Thess, like ordin- 
ary chemical thermometers, are made from special 
tubing with a capillary bore. The bulb is blown by a 
mechanical blower. The arrangement tor preventing 
the mercury running back into the bulb is very simple. 
A very small bulb is blown so that the capillary tube 
becomes somewhat widened a little above the bulb. 
While the tube is still hot It Is nipped or pressed so 
that the enlargement becomes much fiattenedj the 
flattening of this bulb breaks the thread of the mercury, 
so that on cooling the mercury in the tube above the 
constriction remains, while that below runs back into 
the bulb. On heating, the mercury easily rises througU 
the constriction. 



Cyclopaedia of Mechanics. 



127 



Boop-iron Bond for Brickwork.— Hoop-iron liond 
l8 either a plain band of iron, such as is used to 
fasten bales of goods, about 1 in. wide by No. 20 
gauge thiok, or it is stouter, and specially made with 
triangular stabs in it to cause projections, as in 
Tyerman's patent. In either case it is usually tarred 
and sanded, and then laid in the ' courses of brickwork 
parallel with the face, one to each half-brick thickness 
of wall, and at such intervals in height as may be directed 
by the architect. The object is to strengthen the wall, 
' especially where settlements are liable to take place. 
Sometimes it is laid in footings only, at other times at 
the angles of a building ; andagaln, it may be usual as 
a virtual stringcourse round a building between the 
successive floors. The only disadvantage that could be 
caused by its use would be due to rusting if insufttciently 
protected and laid in a damp wall. 

Usual Simple Forms of Hot-Water Apparatus.— 

The sketches below represent the tiro commonest 
schemes of hot-water apparatus in their simplest form. 
They would be erected thus for small property, and also 
for large property if some of the many special require- 
ments or conditions to be found in large houses did not 
exist. Fig. 1 shows the cylinder system of apparatus, to 
which ,this name is given because in it a cylinder is 
nearly always used instead of the square tank. A square 
tank may be used when the apparatus only extends, 
say, 12 ft. above it, but when more than this a cylinder 
is used, because a square reservoir will not bear 
the pressure. The connections must be made as 



a 




Forms of Hot-water Apparatus. 

shown. Draw-offs can be from any point on the 
expansion pipe np to the level of the water in the 
cold cistern. The reason the hot water does not run out 
of the top of the expansion pipe is that this pipe is 
carried up at least 2 ft. higher than the cold-water 
cistern which feeds the apparatus. Fig. 2 shows the tank 
system of apparatus, so called because a square tank is 
used and not a cylinder, although the latter can be used it 
desired (the square tank costs less) . In this apparatus 
the tank is fixed above the highest draw-off, and usually 
only a few feet below the cold-water cistern. The cold 
service is taken into the bottom of the tank, and an 
expansion pipe is taken from the top and carried.to a 
height at least 2 ft. above the cold cistern. Draw-offs 
can only be taken from the flow pipe, not the return, as 
the latter seldom has hot water in it. 

Tuck Pointing and Re-oolourlng Brickwork.— 
The method generally adopted for colouring ordinary 
brickwork is to apply with a brush a solution of 
green, copperas (lib. to 5 gal. of water). This should 
be tried on a few bricks, and allowed to dry before apply- 
ing it to.the whole front ; sometimes two applications are 
needed. Use, when the bricks are of a superior quality, 
a wash formed of I lb. each of Venetian red and Spanish 
brown to 14 gal. of water, in which has been dissolved, 
while the water is hot, ^ lb. of white copperas, or alum. 
This should also be tried on a few bricks, and allowed 
to dry before applying it to the wholo front. The joints 
should be well raked out, and the front washed and 
brushed with a stiff brush. 'When the work is dry, 
apply the colour ; and after this has dried, prepare the 
stopping. The mortar f oi' this is coloured with Venetian 
red and finely sifted smith's ashes orfoundry sand, unless 
red sand can be procured. This must also be tried on a 
few joints and allowed to (Sry'to see that it is of a suit- 
able colour. No more stopping should be done m one 
day than can he jointed, foi- If the -work is allowed to dry 



the white putty will not adhere. The putty is formed of 
finely sifted white lime mixed with linseed oil, and 
silver sand, or marble dust, the latter being preferable if 
it can be obtained. The putty is applied with a steel 
jointer of the width of the joint, on a rule about 7 ft. 
long. The rule should have three blocks of wood, i in. 
thick, on the back, to allow the cuttings from the joints 
to drop clear. The joints are cut with a knife called a 
" Frenchman," the end of which is turned up at right 
angles. The vertical joints are laid on from a board 
formed like a set square, with a wooden handle on the 
front, like the handle on a plasterer's hand fioa.t. It 
should reach three coursesjn height. When the joints are 
all laid on and cut, go over the work with a soft brush 
to remove all dust. A sufficient quantity of oolourinij 
and stopping should be mixed at one time to cover the 
whole. The tuck pointing should be iln. thick. 

Enlarging Photographs] by Daylight.— For making 
enlargements by utilising the window of a dark room, 
construct a bracket A (see illustration) and an up- 
right easel B, running in guiding rails X. Outside the 
window hinge a reflector D, consisting of a white board 
about 24 in. by 20 in., held at an angle of 45° with the 
window sash by a cord S passing through the joint of the 
window frame. The camera 0, preferably one with a 
movement of front for focussing or a lens with rack and 
pinion, is placed on the bracket as shown. The ground 
glass of its focussing screen may he removed and the 




Enlarging Photographs by Daylight 

negative inserted in its stead, or a carrier may be made 
to fit the slide grooves. Another plan is to place the 
negative in the dark slide, removing the partition and 
withdrawing both shutters. The size of the enlargement 
will depend on the distance of the easel from the 
negative and the amount of extension of the camera. 
The flner focussing having been done on a sheet of white 
paper, make a cap of ruby glass to fit over the lens, pin 
up the bromide paper on the easel, and, if the position is 
correct, remove the cap and expose. Light must reach 
the easel only through the negative. 

Staining Fine to Imitate Chippendale.— To stain 
yellow pine in imitation of Chippendale mahogany, 
procure some burnt sienna, ground in water, mix 
with Btdle beer, and add a small quantity of Vandyke 
brown and rose pink; mix well together. Apply rather 
liberally with a brush, then wipe off with clean rag, flnish- 
ingin the direction of the grain. This willf orm the f ounda- 
tion. The exact tone required is built up as the polishing 
proceeds by adding a small quantity of Bismarck brown 
to the polish to impart redness, black for a darker tone, 
and rose pink for the peculiar purple tone that character- 
ises some Chippendale goods. The colours should be 
evenly distributed. Should any difficulty occur in apply- 
ing them with polishing pads, use a camel-hair brush. 

Dissolving Gum Copal.— Copal varies In ciuality, as 
hard, half hard, and soft, and gives best results when 
dissolved in properly heated vessels. Soft gums contain 
a small percentage of water, and if cold turpentine is 
added to the gum when dissolved in spike oil, precipi- 
tation is the result. Copals do not readily dissolve by 
cold solvents unless the gums are powdered ; they may 
then be dissolved in spike oil, if thoroughly mixed. 
To prevent precipitation when thinning out, use one 
part of spike oil and nine parts of turpentine free from 
adulteration. 



128 



Cyclopaedia of Mechanics. 



Demagnetising a Watch. — Place the watch over 
an alternatiDg current tranBformer so that It Is lu 
the magnetic field, and then decrease the current 
gradually to nothing. Another way is to spin a bar 
magnet ,iust over the watch and gradually to withdraw 
it ; or the watch may be revolved over the fields of a 
continuous-current dynamo, and gradually withdrawn 
from the Influence. 

Determining Speed of Photographic Shutter.— 

Choose an object, say the wheel of a hicyele, which 
may he got to make exactly one revolution per second. 
Fasten to one of the spokes near the tyre a disc of 
bright tinfoil, and focus the wheel as large as the 
plate will allow. When the wheel is making one revolu- 
tion per second release the shutter. Now, without 
altering the camera, make an exposure with the wheel 
at rest to serve as a measuring chart. On development 
it will be found that the first exposure shows an arc or 
smudge of light. The proportion which this arc bears to 
the complete circle is the proportion which the shutter 
exposure bears to one second, so that all that remains is 
to measure the arc with a pair of compasses and divide 
the circumference by it. Porabrief exposure of less, say, 
than one-fiftieth of a second, it is necessary to have a 
special arrangement hy which a wheel can be rotated at 
a much higher speed and with greater certainty. 

Fastening Legs to a Bamboo Table Top.— Fig. 1 

shows a simple method! of fastening the legs. Strips 
of deal or other suitable wood are hored to receive 




Fig. 2 
Fastening the Legs to a Bamboo Table Top. 

the top ends of the legs, which are glued and fastened 
with a sprig as indicated. The strips should be halved 
and glued together where necessary (the halving of one 
piece is shown at Fig. 2) , and secured to the underside 
of the top with a few screws. 

Timber-framed Buildings.— There are many ways of 
constructing these, but three methods adopted where 
cost is a consideration are as follows :— (1) Planting 7 in. 
by 2 in. deals on the face of a wall ; (2) framing 
timhers together the half thickness of the wall and then 
.filling in the panels with rough deal studs to receive the 
laths and plaster; and (3) using metal lathing instead 
of the ordinary deal laths. These methods have only 
cheapness to recommend them. To properly construct 
Buch a building, the timhers of all the angles should 
be the full thickness of a 9-in. wall, in fact, 9 in. hy 9 in.; 
Bills, 9in. hy 61n.; heads, 9in. hy 6in.; other timbers, 
such as curved pieces, studs, and rails, 6 in. by 4 in. The 
timbers are grooved on the sides. Jointed together by 
the mortise and tenon joint, and secured by 1-in. oak 
pegs, to project iin. from the face of the wood. The sOls 
should project 14 in. from the face of the brickwork, and 
be moulded and throated on the edge. Between the 
timhers— that is, in the panels— this is iilled with 4i-in. 
brickwork, 1 in. back from the face of the wood, to allow 
of sufficient room for the stucco. Behind the whole of 
the timber framing another 4i-in. wall is built, to make 
it the full thickness of the wall below ; consequently the 
timbers that are the full thickness of the wall will be 
seen from the inside, which should he covered with flat- 
headed nails to form a key for the plaster. After this, 



the outside of the panels is covered with Birmingham 
adamant cement work to J in. in thickness, the groove 
in the timbers acting as a key. The timbers are coated 
twice with Oarbolineum Avenarius, once before fixing 
and once after, 60 that the blackness of the timber may 
contrast pleasantly with the whiteness of the plaster. 
Memel, deal, pitch pine, and oak are each used in the 
construction of half -timber framing. Good red deal, 
if it were possible to obtain it in the sizes required, 
would be preferable to pitch pine, which is liable to 
crack and open under the influence of the weatlier, but 
the use of deal is, from the cause already mentioned, 
greatly restricted, pitch pine being chosen instead. In 
the majority of cases, oak is out of the question on 
account of its cost; but, if a good job is required, and 
when expense is not a prominent consideration, oak is 
the wood to be used. 

Method of Panelling with Veneers.— Wood panel- 
ling, although a very suitable and much-used enrich- 
ment, is genei-ally very costly. The following is a strong 
and effective method of fitting it at a greatly reduced 
cost. First cut some oak veneer into sheets about 2in. 
longer each way than the required panels. Mark the 
lines of the framing on the wall, and glue these 
sheets to the plaster, overlapping the marks 1 in. all 
round. The wall having been previously plugged, 
fasten to it pieces of oak, each about 4 in. by 5 in., to 
form the framing, which thus holds the veneer. The 
joints between the rails and stiles are merely butted. 




FiG. 3 



Fie. I 



FIG. 2 

Method of Wood Panelling with Veneers. 

Sham pins, either cut oft flush or left projecting for i in., 
may be added if desired. Fig. 1 shows an elevation of 
panelling with an old-fashioned treatment of the mould- 
ings, consisting of a double fillet and chamfer run on 
the upright members only, and butting on the horizontal 
ones, which are left square. Fig. 2 is a section illustrat- 
ing the new method of fixing the framing. The panel- 
ling is solid, leaves no space to harbour vermin, 
and can be polished, stained, or otherwise flnisbed 
lu the same manner as ordinary panelling, while its 
cost is considerably less than one-third that of the 
latter. A further advantage is that, as it is much 
thinner than ordinary work, the skirting, 1( already 
fixed, need not be taken up and brought forward j for with 
suitable mouldings on the bottom edge of the bottom rail 
of the panelling a neat junction may be effected. Fig. 3 
shows a method of treating mouldings for this purpose, 
while Fig. i IS an enlarged detail section on the line A B 
in Fig. 1. In Figs. 3 and 4, A represents the framing, B the 
plaster, the ground, and D the veneer. If a bolection 
moulding is preferred, it should be remembered when 
designing it that the general character of a moulding 
arises from the contrast of curves with sharp edges ; and, 
at the same time, the chief divisions of the mouldings 
should not be equal in size, as this tends to produce a 
coarse effect. Two or three small delicate mouldings, 
followed perhaps by a bold ovolo or sootia, and then by 
smaller mouldings again, should, if properly managed, 
give that idea of richness which mouldings are intendBd 
to convey. It may be noted that oak-wood panelling is, 
as a rule, better left rough from the scraper, and, except 
when it is to be polished, not touched with the glass 
paper, as this clogs up the grain. 



Cyclopaedia of Mechanics. 



129 



Painting Clock Dials.— To repaint clock dials, all 
tne old -paint must first be removed, and the plate 
cleaned thoroughly from grease. The -white ground 
can be painted with white enamel, obtainable in 3d. and 
6d. tins. These enamels dry hard and glossy. The 
figures may be painted with black enamel, with a fine 
camel-hair brush. If only a single dial is to be painted, 
the figures may be spaced out on a piece of paper a little 
smaller than the dial plate ; when this paper Is laid 
upon the dial to be painted, the marks can be easily 
transferred to the minute circle. 

Covering a Small Roof with Zinc— A smaU roof of 
the shape indicated in Fig. 1 may be covered as shown in 
Fig. 2, which is a section across one roll at A— B (Pig. 1) ; 
Fig. 3 is a section on C— D of the endroU showing apron to 
weather the joint to brick at the gable end ; and Fig. i 
a section on E— F showing the eaves dripping into a zino 



given, as much as 9 parts water may be used and 10 drops 
per ounce of 10-per-cent. solution of potassium bromide. 
So. 2 : SulpMte of soda, 75 gr. i carbonate of potash, 
100 gr.; glycine, 20 gr.; water, loz. Add glycine last. 
Use 1 part with S parts water. No. 3 : Sulphite of soda, 
50 gr.; water, loz.; amidol, 5gr. The soda should be 
kept as a lO-per-oent. solution, and the amidol added 
only when reauired. No. i: Metol, 3gr. ; sulphite of 
soda, 40gr. ; hydroguinone, 4gr. ; carbonate of potash, 
20 gr; Dissolve the metol first. Use, 1 part with Ipart 
water, and, if necessary, 2 drops per ounce 10-per-eent. 
solution of potassium bromide. The following formula 
for a single fluid developer which will not stain the 
fingers may be used for either plates or paper:— 
Dissolve 24 gr. of metol in 10 oz. of distilled water, add 
loz. of sodium sulphite, 40 gr. of hydroquinone, and 
i oz. of carbonate of potash or soda. For use, take one 
part of developer and one part of water and add 




Covering a Small Eoof with Zinc. 



gutter. In section Fig. 2, 6 is a tack or clip about 2i in. 
to Sin. wide, H the stand-up of the bay, J the roll cap, 
and K a fork or pointed strip with one end soldered to 
the under side of roll cap. On sliding the latter into 
its position, the loose end of the ^ fork passes under 
the clip G and thus forms an invisible fixing. The 
top ends of the bays are turned up against a ridge roll 
which has a capping similar to A— B. If the ridge 
roll stands up about li in. to 2 in. above the others, ■ 
the saddle pieces shown at L (Fig. 1) are unnecessaiT. 
For fixing the eaves gutter, bridging pieces of zinc tube 
are soldered in, and through these long screws are 
passed for fixing to the ends of the boards, or to a fascia 
board if one is used. 

One-solution Developers for Photograpliic Nega- 

tives.- These developers are usually employed for the 
development of snapshot exposures, and are therefore 
compounded for under-exposed plates. The following 
are given ip grains per ounce, from which any quantity 
may be made up by first finding the capacity of a suitable 
bottle and multiplying each item by the number of 
ounces. Use just sufficient hot water to dissolve, then 
fill up the bottle, shaking occasionally. No. 1 : Sulphite 
of soda, 100 gr. ; yellow prussiate of potash, 41) gr. ; hydro- 
quinone, 25 gr. ; caustic potash, 40 gr.; water, loz. Dis- 
solve the potassium hydrate separately. Use 1 part 
with 3 parts water. Where more exposure has been 

9 



1 drop per C)unoe of 10 per cent, solution of bromide of 
potassium. li is preferable to increase this to 4 drops 
per ounce for bromide paper. 

Renovating Plaster Bronzes.— Brush them carefully 
with a soft brush and paint the sm-faoe with gold size, 
and, when this is sticky after standing a short time, 
apply the bronze powder with a pad of chamois leather. 
Dry in an oven till the coating is hard, then apply copal 
varnish and finally stove the bronzes. 

Cementing Leather to Iron.— For uniting leather to 
iron, use marine glue, which is made by dissolving 1 part 
of pure indiarubber in 12 parts of coal-tar naphtha. 
After solution is complete, add 20 parts of powdered 
shellac ; warm the mixture gently, and stir from time to 
time until properly amalgamated. As the naphtha ia 
very inflammable, the heating should be done in a 
steam bath in a closed pan. , When made, the cement 
should be poured on a cold stone and allowed to set. 
Before applying the cement to the iron, the latter 
should be roughened with a file apd heated. The 
leather also should be roughened on the back with 
glasspaper, drawn tightly over the iron while the cement 
is still pasty, and pressed into position until it becomes 
cold. Rubber tyre cement is practically a marine glue, 
and it may be obtained from most cycle-repairing 
depdts. 



130 



Cyclopaedia of Mechanics, 



Making Gelatine Moulds.— When making gelatine 
moulds for casting plaster ornaments, etc., tne glue or 
gelatine must he of good quality; it is soaked 
in water till soft, and melted OTer the fire in the usual 
way. The gelatine must he of juat suflioient consist- 
ency to pour from the can and enter into the fluest 
markings of the model. The mould should first he 
dusted-over with French chalk, which la afterwards care- 
fully brushed off. Before pouring in the plaster, oil the 
mould with paraffin oil in which a piece of composite 
candle has been melted. This will put a clean, smqoth 
skin on the mould, and prevent the plaster from 
sticking. The oast should he removed from the mould 
as soon as possible, and before the plaster begins to 
heat. The mould will peel or scale on the casting through 
using poor gelatine, through not oiling the inside of 
the mould properly, through allowing the plaster to set 
and become warm before being removed, and through 
using the gelatine too thin. 

Self-feeding Poultry Food Bin.— Fig. 1 shows aisec- 
tion and Pig. 2 a front view of the bin, which may be 
made of |-in. pine. The sides are made with the grain 
of the wood running from top to bottom, a ledge being 
nailed across the, lower and top edges to prevent warp- 
ing. A A (Fig. 2) show the lower ledges, those at the 
top being inside. The front (A, Fig. 1) extends from 
the top to a little less than half the depth, and from 
this a piece of tin forms tlie front of the hopper and 
reaches to the feed-hole B (Fig. 1), which should be 
of Buch a height from the ground that the poultry can 



object is 720 in., the focus of lens 71n., the rapidity of 
motion 20 miles an hour or 352 in. per second : then x = 

^ = sJtj of a second, which is the speed at which the 

(UU X oOu ' 

shutter must be worked to obtain a sharp image, assuming 
that the greatest amount of blur or confusion admissible 
in any point of light must not exceed tAu part of an inch. 
It then only remains to find what lens aperture and 
plate will allow of so brief an exposure being given on 
such a subject and in such a light. For example, if f/8 at 
13 noon in June requires ife of a second to secure desired 
density of negative, etc., then f/5'6 will be the nearest 
stop to give the correct result at the same time. 

Black Faint for Lettering on Glass To make a 

black liquid suitable for writing letters ou opal glass, 
take i lb. of lampblack, dry, and place it ou an iron 
plate, well saturate it with turpentine, then set fire to it 
and let it bui-n itself out. This will remove the grease— 
the non-drying oil— from the colour. Now grind it in 
hard drying maatiovamiah, and thin with turps. It would 
be better to give the letters two coats of thin colour 
rather than one thick coat. 

Dyeing Fancy Grasses Various Colours. — Allow 

the grasses to soak for some time in a very hot and 
strong solution of aniline dye in water. Those dyes 
which are not soluble in water may be dissolved in 
spirit, and the solution added to water. Some aniline 
dyes will colour direct in this way, but others require a 
mordanting or fixing agent. For fixing basic dyes, such 





FIG. 2 



Self-feeding Poultry Food Bin. 



reach the grain. The feed-board is hinged to the back of 
the hopper at 0, the joint being protected inside by a 
strip of canvas. A batten D is nailed across the grain of 
the feed-board to keep it from warping, and is extended 
through to the back, where a bolt with a thumbscrew is 
provided which may be turned to regulate the size of the 
feed-hole B to suit the size of the grains of corn that are 
being used. The sides are cut away in the centre at E to 
give a firmer bearing on the ground. A sloping roof is 
provided, fitted with hinges at the front and a hook and 
eye at the back. 

Meaning of Tension, Compression, and Strain.— 

A body is in tension when a force, acting on it 
parallel to its axis, tends to separate its particles by 
drawing them apart. A compression force is one that 
acts parallel to the axis of the body and tenda to force 
the particles into one another. In short, a body in ten- 
sion baa a pulling f orqe upon it, while, if in compression, 
a push would be exerted on it. A strain was at one time 
considered as a force acting on a body, but the more 
modern idea is to consider it as the change of form in a, 
body due to the application of a force. 

Speed of Photographic Shutter.— There is no fixed 
speed at which a photographic shutter should be worked, 
because so much depends upon the strength of the 
light, the aperture of the lens, the speed of the plate, 
and the rapidity with which the objects it is desired 
to photograph are moving. The exposure will gener- 
ally be as long as the moving objects will alio w. When 
the distance from the camera to the moving object 
and the speed at which it travels are known, an 
excellent rule is as follows :— Divide the distance 
between the camera and object (in inches) by the focua 
of the lens multiplied by 100, and divide the result by 
the rapidity of motion (in inches) to obtain the anawer 
in the fraction of a second. Thus, if the distance ot 



as magenta, methyl violet, etc., the grasses should first 
be soaked in a hot solution of oak Dark or of sumach, 
Many pretty shades may be obtained by first soaking in 
a hot solution of picric acid, and then in magenta, 
methyl violet, methylene blue, etc. For green, picric 
acid and indigo extract m8,y be used. In all cases the 
dye solution should be strong and hot, or the dye will 
not penetrate. The grasses should be quickly dried 
after soaking in the colours. 

Tempering Cold Setts for Cutting Steel Rails.— 

The methods of tempering ordinai-y engineers' cutting 
tools are suitable for setts. Warm water is preferred by 
many, but cold water gives a harder temper. Water 
which has been long in use is better than fresh water. 
Chemicals are not necessary, though a little rook salt 
added is said to be advantageous. 

Colouring Malleable Castings.— A good green colour 
is obtained on malleable castings by blackleading 
the castings, and then lacquering them, when heated, 
with a green lacquer. Or they may be painted over 
with bronze powder, which maybe obtained ot various 
colours and tints, rubbed up in best varnish, and heated 
in a hot japanning stove. But the best way is to have 
them bronzed by electro-deposit of copper, brass, or 
other metal ; or they may be tinned in the ordinary 
way, and then lacquered with yellow or gold lacquer 
when heated in a stove or on a hot plate. 

Fixative for Pencil Drawings. — Pencil drawings 
made on ordinary di-awing paper may be protected from 
smudging or becoming blurred by a thin coating pi 
methylated spirit into which some resin has been dis- 
solved. The varnish may be applied with a brush, out 
a better way is to blow it on with a spray, which may be 
obtained at any chemist's. A wash ot milk over the 
drawing will also serve to fix it. 



Cyclopaedia of Mechanics. 



131 



Varnish for Kitchen Chairs.— Such chairs are gener- 
ally made of hirch; the cbmmouest kinds are brushed oyer 
with glue size stained with Venetian red, then Tarnished 
with common varnish heavily stained. The better liinds 
are stained with burnt sienna and size or stale beer, then 
bodied up with red polish and varnished. One penny- 
worth of Bismarck brown, added to Ipt. of varnish, 
imparts a powerful red tone. Shellac ioz., resin 2oz., 
benzoin 2oz., and methylated spirit Ipt., make a useful 
varnish. Carefully strain. If the varnish is not thick 
enough, add more shellac : if it is too thick, add more 
spirit. Apply vrith a camel-hair brush. 

Design for Small Pulpit. -Fig. 1 shows a sketch plan. 
Fig. 2 shows front elevation, with a portion removed on 
the left in order to show the stairs. Fig. 3 shows the 
side elevation. Enlarged detaUs are given as follows :— 
Pig. 4, section through AA; Pig. 5, section through BB; 



black. In pleasure carts it Is customary to have the 
bodies black, without any lines at all, excepting the 
front seats and brackets, but the kind of vehicle deter- 
mines in a great measure the manner in which it is to 
be Unished. It may perhaps be as well to add that the 
broad lines on a trap, usually on the centre of the spokes, 
shafts, and springs, represent "picking out," whilst fine 
lines are the smaller ones sometimes used by themselves, 
when they are called counter-lines, and at other times 
edged on the picking out, or run up the centre of the 
same, when they are termed split lines. 

Boring Holes in Bricks.— For boring holes about 
iin. or |in. diameter at anyplace in an ordinary brick 
wall, an old twist-bit used as a boring tool may be made 
to serve the purpose: a piece of steel tube, such as 
cycles are made with, will, if jagged at the end, answer 
very well. These tools are only suitable where the 




Fulpit for Small Chapel. 



Fig. 6, section through CO; Fig. 7, section through DD ; 
and Fig. 8, section of handrail. The construction is 
fairly simple, but the pulpit would look efEective if 
made of good deal and stained and varnished, or of 
pitch-pine varnished. 

Fainting a Cart.— To be used for trade purposes, it 
would look very well with the body painted chocolate 
lined out with vermilion; the under parts, such as 
shafts, wheels, etc., being painted a light yellow, picked 
out with a broad line of black, edged with vermilion. 
Another colour for hard wear and to look well is a good 
dark green, the body fine-lined with a lighter green, and 
the under parts picked out with the same colour as the 
lines on the body, and edged up, or gauged off with a 
flue line of a straw colour. Blue cannot be recommended 
for the purpose, as it has a tendency to fade and turn 
white ; but if used for the body it should be flne-lined 
veUow and the under parts painted red picked out in 



bricks are fairly soft ; with hard bricks it is quicker 
and easier to make holes with a chisel and hammer 
in the usual manner. Holes may be very guickly 
drilled in brick or stone walls by making the cutting 
end of the drill in the form of a cross with four cutting 
edges. The drill is held in one hand and rotated while 
being struck with a hammer. When the holes are re- 
quired to be deep, a projection may be made < n the 
outer end, by which it can be knocked out of the hole 
quickly. The cutting end should be larger than the 
shank, so as to allow for clearance, and the shank should 
be Bunioiently long to allow a hammer to be used for 
knocking it out of a deep hole. 

White Cement Floor.— For making a hard white 
cement floor for a room, lay an ordinary cement concrete 
foundation, about Sin. thick {4 to l),and on this lay a 
coat, 1 in. thick, of Portland cement and clean white sand 
(1 to 1). Such a floor has a white appearance when dry. 



132 



Cyclopaedia of Mechanics. 



Efficiencies of Water Motors.— For small power pur- 
poses, for pressures ot 60 lb. per square inch and upwards, 
II eCBolenoy is defined as the ratio ot the work re- 
ceived from the motor cdmpared to that put into it, the 
following list may x-epresent tlie effloienoles ot various 
water motors when used in clreumstancea that suit the 
special types considered :— Undershot wheel, 25 to 4S per 
cent, i low breast, 40 to 65 per cent. ; Poncelet, 60 to 70 
per cent. ; high hreast and overshot, 60 to ,80 per cent. ; 
and turbines from 60 per cent, upwards. TJndershot 
wheels and Poncelet wheels are suitable tor heads of 6 ft. 
and under! breast wheels for heads over 6 ft. ; overshot 
wheels, from 10 ft. to 60 ft. or 70 ft, ; and turbines for any 
head according to the design of the wheel. A pres- 
sure ot 50 lb. per sijuare inch corresponds to a head of 
fiO X 2-31 = 115-5 ft. The Jonval (parallel or axial flow), 
Fourneyrou (outward flow), Thomson (inward flow), and 
Schiele (mixed flow) turbines are suitable for pressures. 

Hot-air Oven.— The modern hot-air oven suitable for 
enamelling and japanning here shown is about lOft.-by 
8ft. by 7 tt. high, with iron swine doors in front. An 
ordinary furnace Are, flre-briok lined, is built at the 
further end ot the oven opposite to the smoke flue (see 
Fig. 1, which is a longitudinal section), access to this 



cover. Fold in the corners neatly, and make a small 
roll by running a seam i in. from the outside edges all 
round the top and bottom. For best work these rolls 
are piped with cord. Fill the mattress with curled hair, 
and tuft in rows 6 in. apart with strong twine and red 
woollen tufts. To make the mattress square and flrm at 
the edges the sides are stitched up with two or three 
rows ot blind stitches. For this purpose an upholsterer's 
9-ln. double-pointed mattress needle, threaded with 
twine, must he used, the needle being passed through 
the side about 1 in. from the bottom edge, and brought 
out, but not drawn through, 6 in. from the edge on the 
top; the needle is then, being double-pointed, backed 
out on the side about 3 in. from the place at which it was 
first inserted. When the needle is pulled up tight all 
the hair contained in the stitch is drawn up to the edge 
of the mattress. Stitch all round in this way as many 
times as necessary. 

Design for Bamboo Cabinet.— In the accompanying 
sketch the uprights of top are 2 ft. 6 in. long, the cross 
rails 3ft. 31n., and the mirror 20in. by 15in. Use ij-in. 
or IHn. canes for the work. Make up the front and back 
of the cabinet in the first place, and, while these are 
setting, get ovA the back of the top. The two bottom 
sections should nowbe joined together. The rails should 




Fig 2 

Hot-air Oven. 

furnace fire being obtained by a flight of brick or stone 
. steps. Ordinary furnace bars form the grating, with a 
cast furnace door in front. From the right-hand side at 
the back of the flre-boxthe bviok flue is carried in the 
brick floor, as shown on plan (Fig. 2) , crossing the floor 
three times, and then up the side wall into the smoke 
flue. These flues are covered with fire-brick slabs in the 
usual manner, forming the floor of the oven. On the 
left side ot the back of the fire-box a similar flue is built 
into the back wall in a direction slanting upward; this 
is carried along the side wall, and thence into the smoke 
flue. Doors should be fixed in suitable positions for the 
cleaning ot the flues. If more convenient to have the 
smoke flue in another position, it is only necessary to 
alter slightly the direction of the flues. The size of the 
furnace must depend on the size of theloven adopted. 

STaklng a Hair Mattress. — The top of a hair 

mattress is made of sateen Leeds ticking, bordered 
with fancy striped Belgian. The underside can be 
covered with fine hessian, but if made ot the same 
material as the top the mattress can be reversed. 
Seam the material to the required width of the mattress, 
then machine on a border ot Delglan all round, 5 in. 
wide; this will give the mattress a thickness of 4, in. 
Let the stripe of the border run the opposite way to the 



Design for Bamboo Cabinet. 

be about lOin. between if the cabinet is to be 13 in. wide 
over all. Make the door frames from perfectly straight 
1-ln. canes. These canes should be mitred at the corner, 
and a right-angle dowel should be used tor flUing. The 
rebate for the glass should be formed with split black 
cane. The doors work on pins, which act as pivots. 

Renovating BrasBwork of Bedstead. — Take the 

loose brasswork to pieces and boil ofE the old lacquer 
in a hot solution ot carbonate ot soda and water— 1 lb. 
ot carbonate to 1 gal. ot water ; then swill the parts 
in clean water, Repolish with strips of flannel "list,' 
to which Is applied a mixture ot lime and oil. Then clean 
oft with dry lime, and relacquer with a camel-hair 
brush. The work should be held in some way, preferably 
in a vice. 

Darkening a Mahogany Picture Frame.— To darken 
a Spanish mahogany picture frame, dissolve loz. of 
bichromate ot potash in 1 pt. of warm water. Apply the 
solution with a sponge or crush, getting it well into all 
quirks or hollows; wipe off any surplus with rag. 
Several coats may be given till the desired tone is 
gained. When dry, wipe over with raw linseed oil'j 
smooth down by well rubbing with coarse rag or finest- , 
grade glasspaper. The work may be finished with Frenon 
or wax polish. 



Cyclopaedia of Mechanics. 



133 



How to Make a Pencil Marking Gauge.— This tool 
Is not generally found among woodworkers' ;tools, but 
It it were more adopted it would be found an advan- 
tage over the common rough way of using the Angers 
and pencil as a gauge. It will be seen from the figures 
that there are several ways of making the tool. Any 
bard wood will do for making this gauge, but beech 
is preferable. A piece of wood about 1ft. long and 
lin. thick (see Pig. 1) should be chucked In the lathe for 
the stem of the gauge. This is carefully turned to 
Jin. In diameter, except the end nearest the back poppet 
centre, which is left a trifle thicker than f in., so that the 
head of the gauge inay be turned on It. For the head a 
piece of wood 3 in. square and 14 in. thick will he required j 
two lines drawn from the corners will determine the 
exact centre of the block. At the centre on one side of 
the head a hole should be bored fin. in diameter with 
a sharp centre-bit half through j the block is then turned 
over, and the other half bored; this ensures the hole 
being true. The corners should be cut off the block, so 
that it may be more easily turned ; it la then fixed 
tightly on ■?'here the stem was left thicker ; it should 
be a tight fit. The head should now be turned, so 
that when finished it is just 2Jin. In diameter. To 
improve its appearance, the sides of the head may be 
polished while it revolves in the lathe ; but before this 
is done the top and bottom of the head should be turned 





FiG 4 FIG ^ 

How to Make a Pencil Marking Gauge. 

perfectly square to the stem, and as smooth as possible, 
so that when finished the head should measure li in. 
thick. The stem should then be turned, so that the 
head slides along its length without being too loose; 
the stem is then cut off about 10 in. long, the ends being 
out square. Fittingthe wedge isnext to be done; it may be 
shaped with a chisel or fret-saw. The round on the thin 
end is to prevent the wedge when loosened from slipping 
out and being lost. The wedge should be Sin. long and 
about iln. thick. The groove in the head is out to 
take the wedge ; this may be done with a key-hole or 
fret-saw, finishing with a chisel; the wedge should fit 
easily without any shake. A hole the size of an ordinai-y 
pencil should be bored in the stem about iin. from the 
end ! apiece of pencil is fitted in, and the gauge is com- 
plete. The gauge illustrated in Fig. 2 is octagon in shape. 
A piece of wood 10 in. long Is planed up i in. square each 
way for the stem. The head being octagonal, it is best 
to make it square first ; it should measure 24 in. When 
perfectly true, the comers are cut off; it should be 
marked as shown in Fig. 3. This is done with a pair of 
■compasses. Using the corner of the block as centre, 
and the middle of the block as radius, an arc is described 
to the side of the block ; a line from the ends of these 
arcs marked across the corners, should make a true 
octagon. A square hole to take the stem should be cut 
with a J-in. chisel ; a f-in. hole should be bored through 



first to facilitate the cutting. Care should be taken 
to get the sides of the head square with the stem 
when it is fitted in. The head should also slide up 
and down the stem easily without side play. The 
wedge is cut to shape, and fitted as described for the 
round gauge ; and the pencil Is also fitted as described 
betoi'e. A good way to sharpen the pencil for these 
gauges is with a sharp chisel. It will be found that the 
gauge will be handy in using up odd ends of pencils. 
A different way of making it, which answers well, and is 
less trouble to alter, is shown at Pig. i, which gives the end 
view of the head, showing the shape of the hole. The stem 
Is cut the same shape as the hole in the head, but slightly 
shorter in the flange of the snail. To make the stem, 
take a piece of wood 10 in. long, place the head on one 
end, and mark the shape of the hole oh it. Do the same 
at the other end, and then plane the wood to an oval, as 
shown in Pig. 5. Cut a slot in it with a fine-backed saw, 
as shown by the dotted lines, and round off the inner 
corner. This gauge does not require a wedge to tighten 
it, but is fixed at any desired part of the stem by turning 
round, the shape of the stem acting as an eccentric. To 
loosen it, turn the stem in the opposite direction. 

Frame for Working Embroidery.— The accompany- 
ing sketches of a corner and back view will give an idea of 
how to make a suitable frame on which to work embroid- 
ery. The tenon A (Fig. 1) is 
cut, not in the middle, but 
towards one side of the piece 
of wood, to allow space for 
a groove to admit the 
wedge shown at Fig. 2. The 




Fig. 3 



Fig. 2 



Frame for Working Embroidery. 

dotted part shows how this groove is to be out. The 
mortise is &rst cut to fit the tenon, and a piece chiselled 
out afterwards as shown by dotted lines. This space is 
for the second wedge. Fit the frame together, and tack 
the cloth on which the embroidery is to be done as 
shown at Fig. 2, and, if the hard wood wedges are then 
inserted, it will be seen that by tapping them with a 
hammer they will expand the framework in every 
direction, and thus strain the cloth quite equally. 
Fig. 1 represents a corner of the frame ; Pig. 2 a corner 
with wedges Inserted and cloth tacked on ; Pig. 3 is a 
back view. 

Making tMn Glass Covers for Microscope Slides. 

—The semi-fiuid glass is first blown out into a very 
large thin bulb and the blowpipe swung from side 
to side until the bulb elongates into a cylinder. 
The rounded ends of the cylinder are cracked off by 
applying a red-hot iron wire, and, with a sti-aight wire, 
a longitudinal crack is made from one end of the 
cylinder to the other. The cylinder is placed on a flat 
stove in an annealing kiln for a few moments, when' it 
softens and opensat the crack, gradually flattening out 
into a thin sheet. The circles are made by touching the 
thin sheet with a hot iron wire bent in the form of a 
circle, and the squares are cut out by applying hot, 
straight wires. 



134 



Cyclopaedia of Mechanics. 



Deadening Sound coming through Party Walls. 

—The fault of Bound coming through a party wall 
generally does not lie bo much in the wall itself as In the 
jolBts. It will probably be found that the joistBrest in 
the party wall, possibly touching each other, and that 
the sound is conveyed by the timbers, not by the briolt- 
work. The skirting boai-ds, too, may be acting as 
sounding boards. If this is the case, "jack up' the 
end of each joist, take out the brick below the end of 
it, and insert a thinner brick, with two layers of tarred 
felt between the brick and the joist, at the same time 
wedging a piece of felt between those joists that touch 
each other. The skirtings should be taken off, and the 
space behind filled with plaster. If the cause is really 
in the walls and not in the joists, try covering with one 
of the thick pulp papers, such as Lincrusta-Walton, 
anaglypta, or Japanese leather paper. 

Newspaper Rack in Bamboo,— The rack shown in 
the accompanying illustration has four corner posts, 
each 19 in. long, slightly bent at the bottom to form 
the feet. The posts are connected by three rails A, 
B, and 0, back and front, each 15i in. long, and at the 
sides by rails D and E, each 9 in. long. Tliere are also 
three cross rails running from front to back connecting 
the rails A. The rails B and the posts p (the latter 
being 131 in. long) are halved where they cross. Con- 
necting the posts ris a rail G 15i In. long, to which the 
handle H, of |-in. cane, is fastened. Running from the 



in position. The square hole should be slightly tapered, 
BO that the wedge can be easily released. Eun a saw 
kerf straight through the block B down to the slot, 
as shown at (Fig. 1). The kerf should be just wide 
enough for the scraper S (Pig. 2) to slide freely ; then a few 
rubs backwards and forwards will produce an edge 
which cannot be otherwise than sciuare with the lace. 
It is somewhat difficult for the novice to hold the 
scraper perfectly upright, so as to prevent it from 
swaying from side to side on the oUstone whilst setting 
up the edge. A block something similar to Fig. 1 could 
be adapted for holding the stone, or even a square piece 
of wood might be held on the oilstone to act as a fence 
for the scraper ; this at least would preserve the square- 
ness of the edge. It is when the scraper becomes too 
dull and rounded on the edges by repeated applications 
of the " steel " that the edge requires to be turned over 
to an acute angle with the face. The proper instrument 
lor turning Over the edge of a scraper is a currier's 
"steel," which is a hard-tempered and highly bur- 
nished little tool. Lay it flat on the bench, with 
the edge projecting Jin. or «0; hold it firmly to 
keep it from shifting; grasp the "steel" with the 
right hand, handle downwards, and work it along 
the edge. The " steel " should be held almost perpen- 




Newspaper Rack in Bamboo. 

raU 6 are two 4-in. canes K, each about 19Jin. long, 
pinned together where they cross, and fixed underneath 
the rail D. An inclined rail J runs from B to C, the lower 
end being li in. away from the corner post and the upper 
end belngiSi in. Another rail L, 9 in. long, inclined In the 
opposite direction, meets the rail J about 3iin. from the 
top, and in the triangular opening thus formed panels 
are fixed. The dotted lines indicate how the cane L 
might be fixed if a variation in the design is desired. In 
this case the rail B would terminate where it meets L. 
The centre of rail A is 6iin., and the centre of B 9iin., 
from the ground, and the distances between centres of D 
and E 31 in. 

Sharpening a Cabinet-maker's Steel Scraper.— 

A scraper, to be of au^ use, must have the edge as 
keen and sharp as possible. The contrivance shown 
in Figs. 1 and 2 for trueing the edge of a steel scraper 
does away with the necessity lor a vice, or even a 
bench. It Is so simple that it can be used without risk of 
rounding the edge of the scraper. It is easily made from 
a piece of any kind of hard wood, 4 in. long, 3i in. deep, by 
li in. thick. Dress up the piece of wood to size, and cut 
out the slot A (Pig. 1). The slot should be wide enough 
to allow a flat, fine out file being easily slipped 
through, and it should also be twice as long as the 
file Is wide, so that the lull breadth of the file may 
be made use of for trueing purposes. Bore a i-in. hole 
through the block, and square it out as shown at B; 
this is to take the wedge W (Pig. 2) which holds the file r 



Sharpening a Cabinet-makei's Steel Scraper. 

dicular: an angle of 80 decrees is about right. Then 
the edge of the scraper is turned over in this way, 
the edge of the work bench forms a guide lor the 
hand which holds the "steel," so the operator has 
the assurance that the edge of the scraper is turned 
over to a regular and certain angle. The proper amount 
of pressure to be used can be ascertained only by trial ; 
some scrapers require more force than others on account 
of their difference in temper. A coarsely turned edge 
only works in fits and starts, and is apt to leave the 
work with a lumpy finish ; therefore, when turning the 
edge, do not give the steel too much angle. After 
trueing and setting, the edge should be as keen as a 
razor. Many fail to get a good edge on the scraper through 
trying to turn over the edge when holding the scraper 
edge upwards on the bench. 

RepoUshing a Bath Top.— Scrub off the polish with 
strong washing soda, using a little powdered pumice 
stone or Bath brick to assist. When 'dry, smooth down 
with glasspaper. Bath tops are usually French polished 
with a trace of red in the polish to make them look rich 
in tone. It this is done, and the surface left perfectly 
free from grease, and afterwards given an even coat of 
best quality oil varnish as used by house painters, a 
good wearing surface will be secured. If unable to French 
polish, fairly good results may be obtained by the use 
of a combined mahogany stain and varnidi, as sold at 
paint stores, but a good quality oil varnish must be 
used afterwards. 



Cyclopaedia of Mechanics. 



135 



Wheelwright's Horse for Mortising Wheel Naves. 

—The horse shown in Figs. 1 and 2 is to be preferred to 
the pit for light work. It stands close against a wall, 
preferably under a window; the larger parts can be 
made of deal. Itis Tery light, and can easily be remoTed 
If desired. In Fig. 2, A shows the front of top of wheel horse 
and B the back, each being 4 in. sguare ; o D are the legs, 
3in. square; E Bare two pieces connecting front and back 
of horse together, 2iin. wide by Uin. thick. These are 
driven tightly into a mortise about halfway through 
B and pegged or screwed ; the other ends fit fairly tignt 
in a mortise going right through A, so that the whole 
front of horse, with legs, can be knocked backwards 
and forwards to accommodate hubs of different 
lengths. Two pieces P F, 2 in. square and 19 in. long with 
{-in. bolts, are nailed or screwed on top of wheel horse 
and hoUowed out on top for nave to rest in. To strike a 
curve on front piece, open the compasses 2i in., and for 
back piece 3 in. The nave is fixed with pieces of iron about 
lin. wide and I in. thick, dropping loosely over the 
bolts and spanning the nave at front and back, which 
they are bent to fit. A frame tor a pit for making 
very heavy wheels would have to be a fixture; the 
front might be 71n. wide in the centre, and taper 
on the inside to 3iin. at ends, thus forming a bow 

?4ece to allow for the dish of the wheel. The timber 
or making the pit frame shown in plan. Fig. 3, should 
be Sin. or 4in. thick, the pit being 2ft. 6in. deep. 



pinion, 8; fourth pinion, 6; 'scape pinion, 6. Then 
60 X 60 X 51 X 13 = 2,527,200 ; and 8 x 6 x 6 == 288. There- 
fore, the train = 2-527,200 h- ^= 17,550. Select a hair- 
spring of about Vke required diameter to suit the 
regulator pins, or a little larger, and lay it in position 
on the balance, pushing the brass hairsi)rlng collet 
down tightly upon it to hold it temporarily in position. 
Then hold the outer end of the spring in a pair of 
tweezers, and lift up the balance, just allowing the lower 
pivot to rest upon a watch glass. In this position, 
give it a rotary motion, as in the watch, holding it as 
steady as possible. When once started, the balance 
will continue to vibrate backwards and forwards for 
more than a minute. Have at hand a watch with a 
seconds hand, and carefully count the double vibra- 
tions in a minute, or, for a preliminary trial, in twenty 
or thirty seconds. If thel trial spring is too slow, try a 
stronger one ; it too fast, try a weaker spring. Be care- 
ful to hold the spring in the tweezers at the point where 
it must be pinned into its stud, as a spring that is too 
large for the watch must have several complete turns 
broken off before using, and in such a case must be 
held in the tweezers for counting several turns from the 
outside end. By repeated trials, select a spring that, 
when held at the reciuired diameter, counts the correct 
number in a fiill minute. To pin it into its collet, put 
the collet on a broach and hold in the hand ; cut out 



FIG. 4 




FIG. 3 
Wheelwright's Horse for Mortising Wheel Naves. 



The four mortises G are l|in. square, and the ground 
should be cleared away underneath them so that the 

fleces shaped like Fig. 4 (which are about 22 in. long, 
fin. thick, and 4in. wide at the top) may be knocked 
back from below. The inner surfaces of these holding 

Sieces should be shaved out on the bevel, so that when 
riven In they come into close contact with the sides 
and top of the hub, thus holding it in place. These pieces 
(Fig. 4) take the place of the four thumbscrew bolts of 
the wheel horse. 

Fitting a New Hairspring to a Watch.— It is 

first necessary to know how many beats per hour 
the balance is required to make. This varies according 
to the kind of watch. A Geneva or an American watch 
will lieat 18,000 per hour ; an English watch may beat 
14,400, 16,200, 18,000, or some number between. In an 
English lever, if the fourth wheel has ten times as many 
teeth as the 'scape pinion has leaves, the train is 
18,000 ; it nine times as many, it is 16,200 ; if eight times 
as many. It is 14,400. A watch with an 18,000 train beats 
150 double vibrations per minute, and so on. The 
number of beats per minute of a watch balance when 
keeping correct time may be anything between 
240 and 300. Watch trains are calculated as so many 
beats per hour. Thus, a wWch beating 240 per minute 
is said to have a 14,400 train, and one beating 300 
per minute has an 18,000 train. To ascertain the train of 
any watch, multiply together the numbers of the teeth 
in the centre, third, fourth, and 'scape wheels. Also 
multiply together the numbers of the leaves of the 
third, fourth, and 'scape pinions. Divide the first product 
by half of the second product, and the result is the nTim- 
ber of beats per hour. Thus, centre wheel has 60 teeth ; 
third wheel, 60 ; fourth wheel, 54 ; 'scape wheel, 13; third 



the inner coils of the spring until the collet will easily 
pass through ; then bend the inner end sharply ihwai-ds 
to pin in the collet._ T^o cut out the centre, lay the 
spring on a watch glass and, holding the inner coil with 
a fine pair of tweezers, break off about one-third of a 
turn at a time until it is correct. When properly cut 
out, and the end bent inwal'ds, pass the hairspring over 
the broach upon which the collet was placed, and insert 
the bent-in end for pinning. Pile up a smooth brass pin 
to fit, flat it on one side (to go against the spring), try 
it in the hole before cutting off, and half cut it through 
with a knife ; then insert it, and break off, afterwards 
pushing it home with the tweezers. Then see that the 
spring is flat as it stands upon' the broach, and revolve 
the broach in the flngers to test it. If flat, take it off 
the broach, lay it on a watch glass, and see that it is 
true to centre— that is, that the collet occupies the exact 
centre of the spring, and that the spring starts away 
from the collet freely, and does not " hug " it. Then 
put it on the balance, and again count it for a full 
minute, trying it repeatedly until a point is found at 
which, when held, it counts one beat per minute too 
slow. This is the point at which to pin it in its stud. 
Then try in the watch, and if too slow, as it will be a 
trifle, shorten it until correct. It is always best to pin 
them in a little slow at first, and shorten till right, as, 
if the spring is once made too short, it cannot again be 
lengthened. When finished and in the watch, be care- 
ful to see that the spring lies quite flat, and is free of the 
balance arms and the balance cock ; that its outer coil 
passes freely between the curb pins of the regulator, 
and plays between them nicely : and that the second 
coil does not touch the stud or the inner curb pin, and 
in a Oreneva watch be careful that the outer coil never 
touches the centre wheel. 



136 



Cyclopaedia ot Mechanics. 



stain and Varnish for Towel Rail. — Towel rails 
are usually finiBhed in Imitation pine or mahogany. 
For pine, mix a small quantity of raw sienna with 
stale heer or vinegar; apply with a brush, rubhing 
well into all quirlis, and wipe off the sui-plus with 
clean rag. For mahogany, use burnt sienna. When 
dry, rub smooth with coarse rag or fine glasspaper. 
Then coat several times with spirit varnish applied with 
a camel-hair brush. A more intense red may be gained 
by adding one pennyworth of Bismarck brown to each 
pint of varnish. A suitable varnish consists ot 
methylated spirit, Ipt. ; sheUac, 1 oz. ; resin, 2 oz.; and 
gum sandarach, 2 oz. Dissolve in gentle heat, and care- 
fully strain. 

Mitring a Cornice nTouIding.— The method ot mitring 
the cornice moulding shown by Fig. 1, when the cornice 
is built up as shown by the section (Pig. 2), should pre- 
sent little difftculty in respect ot the members A and 
B. To keep the moulding in position whilst cutting 
the mitre of C, place a strip of wood E in the mitre 
box (Fig. 3) ; the distance from the edge ot this to the 
back of the box must be equal to D (Fig. 2). For ordinary 



Wired tubing is made in the same way, the wire serving 
in place ot the mandrel. Some tubing is made by knead- 
ing between steam-heated rollers the unoured rubber 
with sulphur and inert materials, such as zinc oxide, 
French chalk, etc., and forcing it through a hole in a 
die in which is a plug the same diameter as the tube. 
The rubber tube is drawn away as fast as it is formed, 
then placed in French chalk and heated to 140° F. The 
core of catheters and similar things is an iron wire, 
which is withdrawn after curing. 

Making Fhotographio Carbon Tissue. — Carbon 
tissue may be purchased either sensitised or unsejnsl- 
tised. Sensitised carbon tissue will keep for a tort- 
night, under pressure ; unsensitised tissue will keep 
indefinitely. To sensitise the tissue, immerse it in 
a solution ot bichromate ot potash, and let it dry 
squeegeed in close contact with glass. This operation is 
conveniently performed at night, when, it the room is 
kept fairly dark, the glasses may be placed in the rack 
over the kitchen fire ; in the morning they will be dry. 
Care must be taken to dry the tissues away from -gas or 
oil fumes, as these make the tissue insoluble. Many 




Mitring a Cornice Moulding. 



purposes, mitres made direct from the saw without 
shooting are suitable; the saw must have but little 
" set," and the mitre box must be true. Should easing 
be necessary, use an iron face smoothing plane set Une. 
In more important work where the mitres have to be 
shot, a screw mitre shoot wUl be found very useful. A 
simple form ot shoot can be made by naiUng together 
four pieces ot prepared wood and carefully mitring the 
end, as shown at Fig. i, in which ^the moulding can be 
firmly held while it is being shot by a couple or more 
screws going through the box into the back and top of 
the moulding, as indicated at G and H (Fig. 4) . 

Making Ind'arnbber Tubing. — There are two 
methods of mai^lig rubber tubing. The pure rubber 
is treated with carbon bisulphide or benzine to form 
a dough, which is rolled out into thin sheets and then 
cut into strips. A strip is rolled round a cylindWcal 
mandrel the diameter ot the tube required, the super- 
fluous edges are cut straight along, and the freshly 
cut edges touched with rubber solution and pressed 
together. The rubber is now cured either by soaking 
for the requisite time in a solution of sulphur chloride 
in carbon bisulphide, or by heating in a mixture of 
French chalk and sulphur to a temperature ot about 
140" C. The mandrpl can afterwards be withdrawn. 



good authorities, however, consider that better results 
are obtained when the bichromate is mixed with the 
gelatine before coating the paper. The following is 
Burton's procedure :— Cover 4 oz. ot Nelson's opaque or 
other soluble gelatine with 15 oz. ot water, and allow it 
to sweU tor an hour or so ; then thoroughly dissolve by 
placing the jar containing it In hot water. Dissolve 
Ijoz. of loaf sugar in 2oz. of water, and add to the 
dissolved gelatine. Next dissolve ioz. of potassium 
bichromate in 3oz. of water, and add to it sufficient 
ammonia to give it a decided odour : then mix with the 
gelatine. The favourite pigment is Chinese ink, but any 
pigment in a very fine state of division is suitable ; it 
should be broken up, and made into a stiff paste with 
water. Mix some ot this pigment thoroughly with the 
gelatine in small quantities, stirring vigorously, until 
more pigment has been added than is necessary to 
render quite opaque a thin film spread on pa^er. The 
support must be a good tough paper that wiU stand 
rough handling when wet. Over the top ot a trough is 
then fixed a large glass rod or tube. Two sheets of 
paper are placed back to back, and, one end being 
brought under the rod, the solution is poured out until 
it halt covers the rod; by gently drawing the paper 
round the roller the two outside faces are coated. Hang 
up to dry, and the paper is then ready tor use. 



Cyclopaedia of Mechanics. 



137 



Making Watch Hairsprings. — The operation of 
making watch hairsm-lngs requires special skUl. In 
making by hand, flat wire is fastened at one end tq 
the aroorot a winder not unlike a mainspring winding 
tool and wound up cinlte tight, and kept flat by a 
brass guide on each aide like a bobbin, when wound 
singly and released, the spring will open out a trifle only, 
and the finished spring is a " close-coiled "one. But when 
two or three wires are wound up one over the other, the 
results are more open in the coils. The best hairsprings 
are afterwards fli-e-hardened and tempered, but common 
ones are left soft. They are hardened by being heated 
to redness in a box specially made to exclude the air, and 
then jlunged into oil or water. They are tempered by 
being heated on a metal plate until a slip of bright steel 
, placed beside them turns to a lull blue. They are then 
polished by means of i-ouge and oil on a peg or wood 
polisher (this is very delicate work), and afterwards 
"blued" by heat on a metal plate over a lamp flame. 
These fire-hardened hairsprings are expensive, but are 
always used in the best watches. 

Fastening Tenon Saw to Lid of Tool Chest.— A 

, simple method of fixing a tenon saw on the lid of a tool 
chest is to use a wooden clip, as shown at A (Fig. 1) , which 
holds the end of the saw. The handle can be fastened by 
a button, as shown at B. When the button is moved to 
the position shown by the dotted lines, it will allow of 



black. All trees and foliage shouldbe treated in the 
same way ; the buildings, etc., should be covered with a 
deepened local colour, especially in the dark parts and 
shadows. Windows and illuminated parts should be 
covered with Indian yellow for yellow lights, and with 
lakes for red lights guch as a fire. The dioramic change 
is made by gradually tuiming down the light in front 
and turning it up at the back. The stronger the light 
the better wUl be the effect. 

Making Cyanide of Potassium.— Prussian blue, f erro- 
cyanlde of potassium (yellow prussiate) , and cyanide ot 
potash are now recovered by the Gas Light & Coke Co. 
from the purifying materials used. There are two 
methods of recovering the cyanogen compounds ; the first 
by absorption in the scrubber, the second by absorption 
in the oxide purifiers. In the first method a scrubber is 
used containing soda or potash and some suspended 
oxide or hydrate of iron; the cyanogen in the gas 
combines with the iron and alkali to form ferrocyanide, 
if the iron Is in excess the compound is insoluble 
(probably as Prussian blue), but if the iron is not in 
excess, then the compound is soluble. After a certain 
period the liquid is run off for concentration. In the 
second method the cyanogen is fixed in the oxide of 
iron purifiers as Prussian blue (ferric ferrocyanide). By 
leaving one oxide purifier as No. 1 in the series long 
after it hasbecome saturated with sulphuretted hydrogen 



FIG. 2 U.v*^ 




Fastening Tenon Saw to Lid of Tool Chest. 



the saw being taken out. Pigs. 2 and 3 are enlarged 
sketches of the clip and button respectively. 

Recipe for Dead Black Waterproof Ticket Ink. 

—Take Ivory black or any dry colour and grind (on a 
slab with a muller) in japan gold size to the consistency 
of honey (the proportions cannot be given, as one colour 
will absorb more size than another colour). Now spread 
the colour on a piece of stout blotting paper, and let it 
remain for about an hour j this wUl extract the grease 
from the gold size. Collect the colour in a pot and thin 
with benzine, as the latter evaporates quicker than 
turps, leaving a better flat. 

Preparing Scenery for a Diorama.— The kind of 
cloth used for dioramas is called union ; it is made in 
various sizes, and requires no preparation to receive the 
colours. The subject to be represented is first carefully 
drawn in outline with a pencil. Then mix some Vandyke 
brown with hot double size, and with a fine brush go 
over the pencilled outline. When thoroughl^r dry, the 
painting of the picture may be proceeded with. JeUy 
size is the medium, about 1 qt. of water to a pound of 
size. Only transparent colours should be used, such as 
azure blue, celestial blue, indigo blue, damp lake, brown 
lake, Dutch pink, raw sienna, burnt sienna, Indian 
yellow, Indian red, Vandyke brown, ivory black, blue or 
sky colour. Break up some" whiting and cover with 
water. Take as much a*ire blue as is recimred for 
the sky colour, and make it into a paste with water, 
adding just enough whiting to make the blue flow 
evenly; the colour should be semi-transparent. Cover 
the whole of the picture with this colour, commencing 
at the top and working downwards. As the work 
proceeds the colour should be thinned with the 
medium, so that there may be a gradual change 
of tint from dark to light. All Illuminated parts 
must be thinly covered. When this Is dry, give the 
other portions of the picture their local colouring, 
and finish off. If the other side ot the picture is 
to represent moonlight, draw the moon with a nne 
line and slightly tint it with appropriate colour. Forthe 
dark parts of the sky, use celestial blue ; for the dark 
clouds, indigo; and for very dark clouds, sadden with 



as much as 8 or 10 per cent, of Prussian blue has been 
obtained from it. The oxide of iron is exposed to air in 
the usual way to revivify, and the sulphur extracted by 
carbon bisulphide in closed vessels ; the sulphur is 
recovered, and the carbon bisulphide used over and 
over again. The spent oxide is boiled with lime and 
water, when the Prussian blue is decomposed and ferro- 
cyanide of lime is produced. The clear solution is 
drawn off acidified, and a per and proto salt of iron 
added yielding a pure Prussian blue, which is allowed 
to settle, washed, collected in bags, filter pressed, and 
dried. Prom this pure ferrocyanide of potash is pro- 
duced by boiling with the calculated equivalent of 
caustic potash. Cyanide of potash is formed by fusing 
Prussian blue or ferrocyanide of potash with the right 
proportion of carbonate of potash. 

Sizing and Varnishing Wall-paper.— To size and 
varnish the paper of a hall and staircase, dissolve 
7 lb. of size in 3 gal. of boUing water. When cold 
it will be of the consistency of a weak jelly. 
Apply this to the paper with a double-knot distemper 
brush, being careful to go over every bit of the paper. 
Twelve hours alter, apply a second coat ot size. 
Twenty-four hours after the second coat has been 
applied the paper wUl be ready for varnishing. A good 
paper varnish may be made by well mixing i gal. of 
pale oak varnish, igal. ot turpentine, and Jpt. ot raw 
oU. If the weather is frosty, the stau-case and hall 
should be heated to about 60° P. If this is not praotic 
able, wait until the frost disappears. Spread the varnish 
with a hog's-hair varnish brush, commencing at the top, 
and working evenly downwards. A second coat of 
varnish six months after the first has been applied 
would make a first-class job. 

Preventing Oxidation of Molten Lead.— Strew pow- 
dered charcoal over the surface of the metal; or add 
borax, which wUl fuse and form a layer upon the lead, 
thus excluding the atmosphere. The brown powder Is 
largely oxide ot lead ; it may be reduced by mixing with 
finely powdered charcoal and a little borax and raising 
to a red heat; from it the lead which it contains can 
thus be recovered. 



138 



Cyclopsedia of Mechanics. 



Arohltects' Perspective Drawings.— The perspective 
drawings prepared by arohiteots sometimes have the 
principal lines put in by the rules of geometrical 
perspective as taught In the art schools, hut usually 
they are found hy a special method shown in the 
accompanying diagram, where a very simple building 
Is ohoseu to Indicate the course pursued, 'i'he drawings 



angles of the plan, aa on line a 6, writing the names 
against the chief ones so as to know one from the other. 
A line representing the ground line is then drawn below 





i'*^ 



J^ 



being often on separate sheets, the plan is first fastened 
down on the table by drawing-pins. A suitable point of 
view is then selected, and a common pin stuck in to 
represent the spectator. A narrow strip of paper is now 
fixed by two drawing-pins, and a line ruled upon it in 
the position chosen for the transparent plane, or picture 
plane, which should touch the nearest angle of the 
building, and a straight-edge is used to mark lines 
across the picture plane from the pin to all the chief 




the .position ot spectator, os if the view were a septlon, 
vertical lines drawn from the corners of thebuililinft 
and the heights of the angles set off above the grouna 
line. Dotted lines are now drawn from the extremitie|. , 
of these to the pin, cutting the picture plane in- tns 



Cyclopsedia of Mechanics. 



139 



Mints marked. Now, for the perspective, take a clean 
sneet or paper, and fasten It down on a drawing-board, 
pin the strip ct paper a b horizontal near the bottom 
edge, and project yertical lines from the points which 
represent the angles of the building. Decide where the 
Dottom of the nearest angle in the perspective shall be, 
and above it set off the heights where the dotted lines 
crossed the picture plane, measured from b, and from 
them draw horizontal lines to intersect vertical lines 
drawn from ah. Join the Intersections, and the two 
visible sides of the house will be obtained. Produce 
these to intersect on each side, and the two vanishing 
points will be found. For the remainder draw vertical 
lines from any given points on ab, such as cd, set up 
the height of the parts on the front angle of the perspect- 
ive, such as ef, place a straight-edge from these points 
to line with the vanishing point, and the intersection 
with the vertical lines wUl give the required perspective. 
UeometWcal perspective is useful as giving a scientific 
foundation and reason for the appearances of objects of 
all kinds when viewed naturally by the eye. Ordinary 
drawings of buildings and details are merely conven- 
tional representations, and although theymay be looked 
upon as flat models, and are most useful, they do not 
represent things as they are seen. Architects' perspect- 
ive IS an empirical or "rule of thumb" method suited 
to the circumstances, but not available as a basis for 
the general study of the subject. 

Medicine Cupboard.— Fig. 1 shows a front elevation 
and Pig. 2 a side elevation. It is 2ft. long and 17in. wide, 
and IS fastened to the wall by four mirror plates, one at 
each corner. The four shelves are let into the ends 
about iV in. by sawing two gates and cutting out with a 




FIG. 2 

A Simple Medicine Chest. 

narrow chisel. The doors have imitation panels made by 
mitreing strips, chamfered at the edges, of a plain door 
lln. by iin. The piece sawn out of the top is fastened 
to the edge of the top shelf. The bottom shelf is rounded 
at the corners to bring it to the width of the end, as it is 
narrow where the bottom shelf goes. The ends are of 
i-in. wood, the shelves of l-in. wood, doors ^of J-in. ori-in., 
and the back of l-in. wood. A button on the partition 
wiU do instead of locks. 

Waterproofing Van Sheets.— A waterproof paint for 
van sheets may be made by boiling together, at a tem- 
perature of 500° P. for four or five hours, ligal. of linseed 
oil, 2 oz. of litharge, 2 oz. of umber, and just sufficient 
vegetable black to colour it. Another paint is made 
from leal, of boiled linseed oil, Jpt. of japanners' gold 
size, lib. of vegetable black, and lib. of best patent 
driers. The sheet should belaidupona table and painted 
with either of the above paints, dried in the open air 
for several days, then again painted and dried. 

Disinfecting Books.— If the book to-be disinfected is 
not of much value, burn it. A valuable book may have 
each page dipped in a solution of bichloride of mercury, 
blotted and dried, the covers removed and burnt, and 
the book rebound. Or the book may be passed through 
a hot-air disinfector, the pages being opened so as to 
allow the hot air to pass between them ; and probably 
the book will have to be rebound. A steam disinfector 
is equally effective, but the book will be more damaged 
than by hot air, and the covers will be completely 
ruined, making rebinding a necessity. At Sheffield, 
a disinfecting apparatus is in use in connection with 



the free library, the books being placed in a closed 
chamber in which carbolic acid is vaporised by heat, 
which it is claimed makes the carbolic acid more 
SSr^* ^^^ active! the vaporisation takes place at 
°u -P.. the vapour being raised to about 200" P., snd 
the books being subjected to this process for about 
titteen minutes. It is also stated that books can be dis- 
infected in fifteen minutes in a closed space simply by 
tormaldehyde vapour (or vapour of commercial formalin) 
by using Icub. centimetre of formalin to 300 cub. centi- 
metres, or less, of air. The books may be placed on 
their ends, but the better plan is to hang them up j th6 
covers are opened out until they touch each other, and 
are fastened together, being suspended from the fastener ; 
by this means all the leaves are slightly separated, and 
free access for the hot air, steam, or disinfecting vapour 
permitted. They should never be placed fiat. These 
methods are equally suitable for typhoid germs as for 
tuberculosis. 

ReviTing Polish on Pianos.— Take equal parts of lime 
water, jaw linseed oil, and turps. Well shake the lime 
water and oil till a cream is formed, then add the turps. 
Apply liberally with wadding, and wipe off with rag. 
Clear out aU greasiness, and bring up the polish by 
means of a clean rag made fairly moist— not wet— with 
methylated spirit. Kepeat if required. Should there be 
any peeling off by reason of the paste already on, wash 
off with 2 gal. of warm water, to which has been added a 
teaoupf ul of common washing soda. 

Bed-rest for Invalid.— A simple form of back-rest 
suitable for an invalid when sitting up in bed is 




Fig 2 



■^(ii^/>!!xy^ja!xiifi'j/»:s//^//^/mtmmx& 




FlQ. 1 

Bed-rest for Invalid. 

shown in the accompanying'sketoh. Por its construction 
good red deal, birch, or mahogany may be used. Make 
three frames similar to Pig. 1, the outer edges being 
rounded. These three frames are hinged together as 
shown at Pig. 2, the back frame having a slanting edge 
to fit into the notches of the bottom frame. A pair of 
iron or brass hinged stays, fixed at the sides, will prevent 
the sliding back from slipping. 

Lacquering Brasswork.- To relaoquer fire brasses, 
curbs, etc., have them perfectly free from grease, and 
heat them on a hot plate of some kind, and when hot 
enough apply the gold lacquer with a camel-hair brush ; 
then place them on the hot plate again for a short time. 
Take the articles off and allow to cool; do not touch 
them whUe hot with the fingers. 

Polishing Teak to Resemble Rosewood.— To 

stain and polish teak to represent rosewood, dissolve 
one pennyworth of Bismarck brown in Ipt. of hot 
vinegar and water (equal parts). With this, brush 
over the article once or twice. When dry, wipe over with 
" red oU," which is made by steeping 2 oz. of alkanet root 
in i p1f. of raw linseed oU. The work is then ready for 
polishing. As teak is a hungry wood, to gain good 
results a grain filler should be used. Mix finely crushed 
dry whiting into a creamy paste with turps, colouring it 
to match the wood by adding Venetian red and vegetable 
black or lampblack. Eub well in in order lo fill Up the 
grain. Wipe off clean, leaving the surface of the wood 
free from paste, and polish in the usual way, adding 
Bismarck to the polish to give a reddish tinge; if a 
darker tone is desired, a trace of black may be added. 



140 



Cyclopaedia of Mechanics. 



Erasing and Re-engraving Initials on Watoh Case. 

—To erase Initials from a watch case is a delicate job. 
If the letters are in the centre of an otherwise plain case, 
tsike a fine flat file (costing about id. at a jewellers 
material dealer) , and, with short, Arm strokes, file out 
the letters. Then go over the surface with a piece of 
snakestone or Tam-o'-Shanter hone, and finish with 
putty powder on a piece of soft leilther. It the letters 
ai-e in a small shield, the tendency is to damage the 
outside work, which would require to be re-eut. With 
a small rilBer, or bent fUe with a flat surface, file out 
the letters, dress with snakestone fashioned to a point, 
and finish as described abOTe. If new initials are re- 
quired, first draw them in pencil, and scratch them on 
with a point or etching needle. Then whet up a craTer 
at moderately sharp angles, outline lightly, put in the 
thickening cuts, relieve the whole with light and graceful 
sprigged work, and then clean up. 

Combined Jewel, Glove, and Handkerchief Case.— 

A case made in the form of Pig. 1 will be suitable for 
holding jewels, gloves, and handkerchiefs. It Is 14in. 
by 8 in. by 9 In. deep, and contains two drawers, 
one to receive handkerchiefs and one to receive 
gloves. The upper jjart is fitted with a tray to lift 
out ; this is to hold jewellery. Figs. 3 and 4 are plans 
of the two drawers. Fig. 2 is a plan of the tray ; the 
centre part A Is movable, and is arranged to hold a 
watch, the latter lying on a cushion formed on a piece of 



citric acid. This tends to Improve and retain the bright. 
nesa of the image, by dissolving out the remaining iron, 
and preventing the deposition of a white precipitate 
over the blue. It Is very desirable that the paper should 
not in any case be washed for a lengthy period. 

Tinning Inside Copper Pipes and Brassworh,— 

For tinning any metal it is first necessary to oleaa 
it from dirt and sand and remove the surface which Is 
oxidised or tarnished. This surface Is removed by pick- 
ling the metals for a few hours in clean water containing 
a small quantity of sulphuric acid. The metals are then 
dipped in chloride of zinc, and afterwards laid in a bath 
of molten tin, out of which they are taken and held up 
for the surplus tin to drain oft. It is doubtful whether 
this process is entirely satisfactory for artificial mineral 
waters, as the so-called tinned surface partakes more of 
the nature of an alloy of tin and zinc. Unless the proper 
appliances are at hand. It Is cheaper and better to buy 
the copper pipes already tinned. It is also probable that 
white-metal cooks or taps would answer equally as well 
as those made of brass, which would have to be tinned 
before being ground in. 

Contents of Tapering Vessels.— A gallon of water 
occupies 2T7'27cub. in., and the capacity of the frustum 
of a cone can be obtained by adding to the sum of the 
ai-eas of the two ends the square root of their product 
and then multiplying by one-third the vertical height. 





FiQ.'2 




Fia 1 



l^\\\\\\\'\\'\V 



F,a 3' 



Combined Jewel, Glove, and .Handkerchief Case. 



T^Ii-in. wood. The part at the back Is left open to allow 
the watch chain to fall into the drawer or box under- 
neath the cushion. The back part of the tray is fitted 
with four compartments to receive trinkets, etc. j the 
side parts marked B, with ribbon loops, are for pins, 
brooches, etc. ; the sides marked are slotted to receive 
rings, etc. The whole of the Interior Is covered with 
velvet plush, the inside of cover of the case is fitted 
with a bevelled mirror, and the sides are lined with 
plush, and buttoned. If a smaller case is required, make 
a box In the ordinary manner, and fit It with a tray 
as i ig. 2, omitting a compartment in length. To line the 
drawers of the glove box rebate the inner upper edge of 
the drawers as shown In the accompanying sketch, and 
after fixing the lining A, fix in the bead B. T is the top 
edge of the division and r the front of the box. The 
divisions should stand lower than the upper edge, and 
In covering, the lining should be stretched over the 
top edge, the raw edges being carried to the bottom. 
Glue, if used thick, will not spoil the pile ; if used In 
n thin state, the glue will percolate through the founda- 
tion, and so spoil the velvet. 

Hints on Printing Blue Photographs The de- 
tails of the picture should be fuUy out, and the dark 
parts should have a bronzed appearance. Careisrequired 
to prevent the blue becoming less Intense, and-there- 
Jore the white lines not showing up so much. A pi'int 
too much exposed appears weak, but the same occurs 
with too little exposure. The ferricyanide used should 
be as pure as possible. It is affected by air and light, 
which may change It into ferrooyanide. The first forms 
a blue pi-eoipitate, and the second a white. Crystals of 
ferricyanide should therefore be rinsed befoi-e use to rid 
them of the changed outside covering. The first wash- 
ing water should be acidulated with hydrochloric or 



The contents will be in cubic inches if the areas and 
heights are measured in square inches and inches 
respectively. Of course, there are many varieties of 
tapering vessels that will hold 1 gal., but, assuming 
that the diameters are 3| in. and .41 in. at bottom 
and top of the vessel respectively, the .height can be 
determined as follows :— The areas of the two ends 
will be 3i X 35 X -7854 = 10-3 sq. in., and 4i x 4i x -7864 
= 14"2 sq. In. respectively j the product of these is about 
144, its square root being twelve. The sum of the ends,' 
etc., is therefore lO'S -I- 14-2 + 12 = 36-5, so that the height 

should be 3 X ?^ = 22'7in. (say). 

Btching on Copper.— A copper plate is polished, and 
fixed in a mixture of resin and beeswax by warming the 
wax and laying the copperplate on. All grease is removed 
with whiting, the surface of the copper coated with fine 
wax, and the pattern drawn with a fine etching needle 
passing through the wax to the copper. Nitric acid is 
then applied to the surface ; this eats into the copper 
plate where pricked with the etching needle, the wax 
^eventing the acid from biting in places not required. 
When Bulflclently bitten in, the plate is removed, the 
wax warmed and pulled carefully off, and the plate 
cleaned with turpentine. 

Making Night-liglits. — Nlght-Uguts are made by 
melting the material and pouring it into metal 
moulds in which the wicks have been prevlouslolaoed. 
The commoner night-lights are made from parafSn wax, 
whilst the better ou6s are made from stearin (the fatty 
acids which are obtained from tallow or palm oil by 
saponification and pressure) -, or from composite, a 
mixture of paraffin wax or cerasin with stearin {gl/yceryl 
trietearate). 



Cyclopaedia of Mechanics. 



Ul 



Copying a Mounted Photograpli.— The print should 
be copied in contact with glass. Presuming the print 
is upon an ordinary mount (that is, not set hack In a 
cutout mount), place it In a frame containing a per- 
fectly clear sheet of glass, and press into close contact. 
Set up the frame facing a full light, care being taken to 
avoid reflection by covering up objects that are reflected 
in the shadows of the picture. If a studio is not available , 
the copying should be done out of doors in full sunlight, in 
which case it may be possible to avoid grain without copy- 
ing under glass. Slow plates are the most suitS,ble, but 
much depends upon the degree of contrast in the print, 
the printing process to be used, etc. For example, it the 
copy is very hard, and the picture is to be printed upon 
P.O.P., use a quick plate and the usual developer. If, on 
the other hand, the copy is flat and wanting in contrast, 
and the negative is for printing in carbon or for repro- 
duction, use a process plate and hydrociuinone developer. 

Position of Mast in Canoe.— The centre of effort 
of a single lug-sail should be about 3 In. ahead of the 
centre of lateral resistance of the immersed portion 
of the canoe's hull ; the correct position of the mast 
will therefore depend on the position of the centre 
board. It any, or the shape of the keel, neither of which 
is given. The centre of any triangle's area is the point 
at one-third of the line from the centre of any side 
to the opposite angle. Hence, if the sail be divided by 
line AC (see sketch) the points E and V will be the cen- 
tres of triangles ABC and A C D respectively. Join these 
points by line E 1?. Again divide the sail by the line B D, 
find G and H the centres of triangles A B D and BOD; join 
G and H, which line intersects EF at 3, the "centre of 
effort " of the sail. To ascertain the centre of resistance, 




o c 

Position of Mast In Canoe. 

let down the centre board, place the rudder amidships, 
and let the crew on board hold' one end of a string in 
such a position that when the other end is steadily 
puUed by a second person, the canoe will approach the 
latter, remaining at right angles to the string. Mark 
this position, and step the mast in order that the sail's 
centre may be 3 in. or 4 in. ahead of it measured horizon- 
tally. The rudder stock must not extend below the keel, 
but the drag maybe curved to 4 in. below it and 
extending aft to 10 in. A nearly vertical stern-post is 
advisable. 

Power trom Waterfalls, Tides, etc.— The different 
methods by which water can be made to perform me- 
chanical" work are: First, by its weight; second, by 
shock, as when a stream of water Impinges at right 
■ angles on a moving surface ■ third, by action or im- 
pulse, as when an unconflned stream or water meets a 
moving surface, the relative velocityJiaving no portion 
at right angles to the surface, but gliding along and 
ultimately leaving the surface; fourth, by reaction, as 
when a stream of water enters, flows through, and 
ultimately leaves a moving pipe or channel, which it 
completely fills ; and fifth, by a combination of two or 
more of the above methods of action. The classification 
of the motors may be as follows : (a) Water wheels (the 
water acting on the outside of the wheel) are either 
undershot,' breast, or overshot wheels ; (6) turbines (an 
arrangement where the water acts through the inside of 
the wheel) are either on the axial or the radial fiow 
system, and may work either by reaction and impulse 
combined or by pure impulse alone. Water power is 
useful for any industi-y requiring slow-moving, regular 
power, such as corn-grinding, ore-crushing, chemical 
mixing, etc. Tide motors may be on two systems : in 
the former, the tidal waters rush through a small 
opening into a reservoir, actuating a turbine which is 
fixed in the opening, and the ebb water rushes out 
through another opening (the first opening being closed 
by a penstock or shutter) actuating another turbine. 



The cost of the reservoir, which is practically a tidal 
dock, is very great. In the other system, a series of 
wooden gates hanging from a frame are set in motion by 
the rise and fall of the waves, and their motion is con- 
veyed by cranks and rods to an engine. Tidal motors, 
especially the latter form, are only available for 
purposes not requiring regularity, such as pumping 
water for keeping a reservoir replenished. 

Rubber Solution for Patching Mackintosh.— 

Rubber solution must be made from indiarubber 
which has not been vulcanised; Para rubber is con- 
sidered best for the purpose. The rubber should be cut 
into thin shavings with a very sharp, wet knife. The 
shavings may be dried, then placed in a dry, wide- 
mouthed bottle, and covered with benzene (coal-tar 
naphtha) or carbon bisulphide. Benzene is preferable, 
as it does not smell quite so strong as carbon bisulphide. 
The bottle should be tightly corked, placed in a warm 
place, shaken from time to time, and more solvent added 
as the rubber swells. One ounce by weight of rubber 
will take from 15 oz. to 20 oz. by measure of the benzene. 
This solution will be found suitable for patching a 
mackintosh or for use In places where rain penetrates, 
but as a dressing for re- waterproofing it will not stand. 

Electric Alarm Device for a Clock.— The diagram 
below shows how to attach an electric bell to a clock, the 
bell to ring at any given time. A' is an alarm device 
cemented to the face of the clock. The flexible wire 
at B is connected to the battery at 0, and thence to 
the bell D and make and brealt switch E. The terminal 
connected to the pivot of the switch may be connected 




Electric Alarm Device for a Clock, 

to a terminal IT fastened on the clock case. Thus a com- 
plete circuit is formed with the whole of the api)aratua 
in series. 

Polishing Tarnished Copper. — The quickest and 
cheapest method of polishing tarnished copper is to 
buff up the article on a polishing machine; if this 
is impracticable, it may be polished by hand. To do 
this, mix some fine flour emery with sweet oil until a 
thin paste is formed, and, using a piece of house flannel 
as a pad, scour the tarnished surface with the paste 
until the surface is quite clean. Wipe off the oil from 
the copper, and with a dry piece of flannel dust the copper 
over with crocus powder, and polish with this until quite 
bright. 

Painting Canvas Canoe.— Both sides of the canvas 
material of the canoe should be painted. The object 
in painting the inside is to prevent any water getting 
between the framework and the skin and thus rotting 
the canvas. Particular attention must be paid to all 
inside corners and edges of the stringers j the frame also 
must be painted before stretching the skin. There is 
nothing better than ordinary paint, but see that the 
white lead is good and not half whiting. Use plenty of. 
boiled oil for the last coat, as salt water tends to harden 
paint. There is not much difference as to the durability 
regarding the effects of salt and fresh water. 

Removing Brunswick Black.— To remove Brunswiok 
black from a stone mantelpiece previous to painting it, 
use American potash dissolved in water, and made into 
the consistency of paste by adding newly slaked lime. 
Apply this with an old brush, and let it remiain on for 
a few hours, then wash off ; if the first attempt does not 
remove the black, repeat the process. Care must be taken 
when using the potash, as. it is dangerous to fingers and 
nails ; should any of the liquid get on the hands, they 
should be at once well washed in water containing a 
little vinegar or a few drops of acid. 



142 



Cyclopaedia of Mechanics. 



Preventing Ru&t .In Kitchen Boiler.— A boiler can 
often be cured ot rusting by giving it two or three coats 
of limewash to which has been added a little size to act 
as a iixative ; about the same proportions should be used 
as in making a whitewash for a ceiling, but builders' 
ordinary quioltlime must be used. The first coat must 
be well rubbed in. Before applying the limewash the 
boUer should be thoroughly cleaned, and as much rust 
as possible removed from the surface ; then let it dry. 

Meaning of Term Kilowatt. -This is a measure of 
electrical power or rate ot doing woric, and means 
1,000 watts. It is usually applied to large electrical 
outputs, and can be determined by multiplying tlie 
electro-motive force in volts by the current in amperes 
and dividing by 1,000. Thus, if the electro-motive force 
at the terminals ot a circuit were 200 volts, and the 
cui'rent in the circuit 250 ampJres, the output would be 
200 X 250 = 50,000 watts, or ^''■°"°= 50 kilowatts. 

Sham Timber Building.— The usual way to get an 
appearance of old-fashioned timber work on a house is by 
nailing boards on the brickwork to represent the framed 
timber and plastering the intervening spaces flush with 
the -wood ; the plaster to be afterwards whitewashed, and 
the boards painted a darlc brown. Tolerably stout deal 
boards should be used, and for plaster, Portland cement, 
with a fair propoi'tlon of sand, is advised. The arrange- 
ment of the sham timbers is a matter of taste ; but 
suggestions are given In Figs. 1 and 2. By the " look-out 



note. If two notes are used together, they may be 
nearly alike as is the duplex vfhistle used by ths 
police, or they may be tuned in the Interval of a third 
major or minor. The combination ot two sounds nearly 
alike gives rise to "beats," which are very eftective as 
" noises." With two sounds representing the dot and 
dash of the Morse alphabet any signal can be trans- 
mitted. 

Distinguishing Good and Bad Fur Skins.— When 
appreciating the good and bad points ot skins of mink, 
marten, and other fur-bearing animals, every skin has 
its own special points, and age, season, and even sex 
must be taken into consideration. In a general way, 
the pelts of immature animals will be of little value- 
those from breeding females will in most cases be of no 
use— and every hole or tear will take off some value even 
from good skins. The best skins are obtained during 
the coldest parts of the severest winters, when the 
underlying fur— the soft, downy part nearest the skin- 
will be thickest, and the internal part of the actual skin 
most free from black spots and patches. 

Graining Walnut in Water-colour For the ground- 
work, give a coating of white lead 2 lb., Oxford ochre 
2oz., Venetian red 2oz., burnt umber loz., thinned 
with equal parts ot turps and boiled oil. Bamp the 
work thirty-six hours afterwards with water 7 parts, 
beer 1 part, then brush it over with weak beer, burnt 
sienna, and a little Vandyke brown, and, when dry, 
mottle it with a large mottler. JSTow over-grain with 




FlQ. 1 




Fia 2- 



Sham Timber BuUding. 



In the root" it la presumed that a dormer window is 
meant. The illustrations show such a window, which 
recedes a little from the eaves. It rests on, and is 
framed to, the rafters ot the roof. Its triangular sides 
and gable will be of lath and plaster. In the elevation 
(Fig. 2) a roughly carved barge board is shown in the 
gable. This adds much to the effect, and should not be 
omitted. 

Enamel for Coating Pills.— Finely powdered French 
chalk forms the white enamel used as a coating for 
pills. The pills are first dipped in a sugar syrup con- 
taining white of egg, then placed in the chalk in an 
agitating machine, the shaking thus polisbing the outer 
surfaces of the pills and producing the enamel-like 
surface. The shaking could be done in a tin box if 
desired. 

Far-reaching Signal Sounds.— An oi'gan reed— that 
is, a reed with a vibrator larger than its aperture— 
produces a more powerful sound than any instrument 
ot the flue-pipe variety. The wind pressure in each 
case being equal, a low note can be heard at a 
greater distance from its source than a high note, but 
a low note requires a larger tube. A note within 
the limits of a man's voice, say low P, would be suit- 
able. This note could be produced with a tube about 
B ft. long. A great pressure of wind is not required. The 
most powerful organ pipes speak under a pressure of 
about the weight ot 12 in. of water, that is, about 631b. 
to the square toot, but everything depends on the 
weiEht and flexibility ot the vibrator. The conical tube 
used for a speaking trumpet is a suitable shape for a 
mouthpiece. Two instruments could be adopted, which 
may be used either together or alternately. A short 
sound followed by silence is better than a continuous 



a hog-hair over-grainer dipped into a thin mixture ot 
Vandyke brown and weak beer; use it very freely, 
and soften upwards only. While this is wet, the dark 
veins and curls should be put in with an over-grainer. 
using drop black thinned with weak beer. Soften in all 
directions. Glaze or shade with drop black and a little 
Indigo. Do not overcrowd the work. When dry, it ia 
ready for varnishing. Take as a pattern for the graining 
some article of furniture in walnut, such as the case of 
a piano. 

Oak Finish for Yellow Pine. -Staining and French, 
polishing will give the colour ot oak, is generally 
considered the best finish, and is readily cleansed. 
Pine finish Is easier to gain j generally the polish only 
will give it this appearance, especially it dark-coloured 
shellac is used. Mahogany and walnut tones are 
considered superior, the colour being gained by first 
staining. Oak Is not advised as a first effort: to 
make the work look really well, and pass for oak, 
requires rather clever treatment. Shellac, 6oz., dis- 
solved in 1 pt. methylated spirit, makes French polish as 
used by most polishers. It gives best results when 
applied by means ot polishing pads, but it applied with a 
camel-hair brush 2 oz. of resin should be added. 

Varnishing Oil Paintings.- To finish oil paintings 
that have not been varnished, they should not, as a rule, 
be entirely coated with varnish, as this will tend to make 
them ob.ieotionably glossy. Whenapaintinghas become 
thoroughly dry, certain parts of it will be much duller 
than others, and these parts may be brightened by 
applying a little raw linseed oil with a hog'sOialr brush. 
It the whole picture is dull and requires varnishing, ft 
thin coat only of varnish may be put on. Both varnish 
and oil should be bought from an artists' colourman. 



Cyclopaedia of Mechanics, 



143 



PoUshlBS Flooring. — first coat the floor with a 
solution of patent knotting, made by adding i gal. 
of metliylated spiWt to each gallon of knotting. Place 
near the fire for halt an hour ; shake well hefore using. 
On e hour after applying the first coat, glasspaper slightly ; 
then give another coat. Now take some crude paraffin 
or paraffin wax and thin with turps j put this on with a 
brush. Ifow take a 14-lh. polishing iron, which has a 
long handle like a sweeping brush, the iron working on 
a swivel, heat it on a coke fire, then work it rapidly to 
and fro over the flooring. Do a small piece of flooring 
only at one time. ' 

Perforated Metal Screen for Window.— To make a 
perforated tin or zine screen for a window frame 35 in. 
wide by 30 in. high, cut from the metal sheet a rectangle 
311 in. by 29iin. A tube frame round the edge makes 
a neat and strong finish. Now cut two lengths of S-in. 
split brass tube 35 in. long, and two lengths for the ends 
30 in. long i make the cuts at an angle of 45° so that the 
pieces of tube will mitre, and measure the lengths along 
the side of the tube opposite to the split seam. Place 
the tubes in position round the perforation, solder the 
corners strongly, and solder a semicircular-shaped piece 
of metal with a hole punched in it to the tube at the top 
corners, so that the screen maj' be hung on two brass 
hooks fixed at the sides of the window. Clean off the 
solder at the mitre joints, polish the tube, and enamel 
the perforated part green or other suitable colour, and 
the screen is finished. 

Simple Folding Table.— Pig. 1 is an underneath plan 
of the folding table. A narrow frame A, about 2 in. 
deep, is fixed by means of screws or wood buttons to 
the underside of the top. The legs are connected to 
end pieces B, and fold inwards. The connecting pieces B 



to any desired shape, and after evapoi-ation of the 
alcohol this material becomes quite hard. To cheapen 
the material, large quantities of starch, zinc oxide, 
whiting, or barytes are mixed with the above material, 
yielding the ivory or bone-like products usually seen. 
The coloured varieties are made by incorporating pig- 
ments with the celluloid, and tortoisesheil and other 
forms are made by special treatment. To soften cellu- 
loid, break it small, add a small quantity of camphor, 
and then add sufficient spirit to cover the mass. After 
standing a few days it will be soft enough to work. 
Horn can be softened, but not dissolved, oy treating 
it with caustic soda for a short time, whUe prolonged 
action of the alkali will convert it into glue. 

Copying Manuscript by Photograpliy.— The cheapest 
plan of copying manuscript books is to use one of the 
ordinary methods of copying written matter. This, how- 
ever, necessitates the first copy being written out with 
special ink. If the writing is on one side of the paper 
only, procure some fairly pure paper and mix together 
(A) potassium ferricyanide 2ioz., water 10 oz.; and (B) 
ierri-ammonium citrate 2i oz., water 10 oz. Mix an equal 
quantity of each, and coat the paper by rubbing the solu- 
tion well over it several times with a soft sponge or tuft 
of cotton wool. The paper should be coated as evenly 
as possible, but no notice need be taken of streakiness, 
so long as the paper has been well covered. A convenient 
tool consists of a glass tube through which slides a loop 
of fine wire holding a tuft of wool. When pulled up 
tight, the wire is wound around the top of the tube. As 
the potassium ferricyanide is exceedingly poisonous. It 
is not advisable to get more on the fingers than can be 
avoided. The paper is printed in contact with the draw- 
ing or writing in the usual pressure frame, or the sheets 
may be fastened together with wooden clips between 




FK3. I 



Simple Folding Table. 



are rebated on the inner edge, 6 in. by i in. The piece C 
is 6 in. wide and t in. thick, and is screwed to the centre 
of the table top as shown. This piece fits into the 
rebates cut in B, and serves as a spring to keep the legs 
rigid when the table Is set up. Pig. 2 is a half elevation 
of the table showing the spring fixed in the leg. 

Fainting Compo Work on Building. — To paint 
stone-colour newly compoed work on the front of a house, 
mix well together 7 lb. of dry red lead, i gal. of boiled 
oil, 1 qt. of turps, but no driers. Coat the compo with 
this, and. let it stand for forty-eight hours. TiTow take 
71b. of white lead, 4 gal. of boiled oU, 1 qt. of turps, and 
41b. of patent driers, and give the compo two coats of 
this, letting it dry well between each coat. Forty-eight 
hours after the last coat, take 71b. of white lead, 41b. 
of yellow ochre, and 41b. of patent driers; thin with 
boiled oil so that it will cover nicely. Por washing down 
the remainder, boil in 1 gal. of water until dissolved 41b. 
of soap cut into thin shreds, then add one tablespoon- 
fnl each of alum and carbonate of ammonia. Apply 
thoroughly with a brush, and wash off with cold water 
before the ammonia has had time to act on the paint. 

Asphalt Damp-proof Course.— An ordinary damp- 
proof building course may be made. by mixing 12 gal. 
coal-tar, 4 cwt. pitch, and 2 gal. creosote oil. It will 
take nearly an hour to melt this quantity, and it 
should not boil more than a few minutes. After being 
poured upon the wall, which should be first swept and 
quite dry, it should be sprinkled with sand. The above 
quantities wUl cover about 12 sq. yd. 

Composition for Making Cheap Combs.— The combs 
sold at a penny each are usually made of celluloid, 
a composition produced by treating collodion cotton 
with camphor and methylated spirit. The camphorated 
spirit dissolves the collodion cotton sufficiently to 
convert it into a gelatinous mass which can be pressed 



two pieces of glass. Printing on this paper requires a 
longer time (six to ten times) than silver paper ; but on 
taking the print from the frame it merely requires 
■washing in water, to the first bath of which it is advisable 
to add a little citric acid. This procesa gives white 
letters on a blue ground. Por black lines on a white 
ground the following is recommended. Make up three 
stock solutions : (A) Gum 1 part, water 5 parts. (B) Ferrl- 
ammonium citrate 1 part, water two parts. (C) Ferric 
chloride 1 part, water 2 parts. For use, take (A) 30 
parts, (B) 8 partSj (0) 5 parts. Develop with potassiuni 
ferrocyahide (or yellow prussiate) 60 gr., water loz., 
and fix in a lO-per-ceut. solution of hydrochloric 
acid. If the writing is upon both sides of the paper, 
the only plan wUl be copying through the camera. 
The book must be taken to pieces, and pages in consecu- 
tive order arranged on a board to go as near as possible 
into the size plate to be used, and copied on process 
plates, using hydroquinone developer. From these nega- 
tives enlargements could be made, or the optical lantern 
could be used. Great care must be taken to get a 
thoroughly sharp negative : use a lens with a flat field or 
a small stop and keep the negatives fairly thin. If, for 
example, the pages are 6 in. by 4in.,then twenty-four 
of these could be copied in one exposure on a half-plate, 
making seventy-five exposures in all. The wet collodion 
would be the best and cheapest process to employ. 

Removing Iron Stains from White Marble.— 

Surface iron stains may be removed by applying a 
solution of oxalic acid and then washing with water ; but 
it the stains have penetrated through the marble, they 
cannot be removed. They mjiy be covered by applying 
a little lime cream (lime slaked with water) and, after 
drying, brushing over it a solution of silicate of soda, but 
this coating would be without polish. On highly polished 
marble, zinc- white ground with copal varnish and turpen- 
tine carefully applied might serve to cover the stains. 



144 



Cyclopaedia of Mechanics. 



BemoTlng Damp Stains from Pictures,— To remove 
damp stains from prints or engravings, they are im- 
mersed in a bath containing chloride of lime. Pastels, 
water-colours, and pencil sketches are more difficult 
to ivork upon ; in fact. In the case of these latter it is 
almost impossible to remove damp effectually. 

Double Seats for Sbop.— Figs. 1 and 2 show the ends 
of two seats different In design for the centre of a shop. 
Fig. 1 is a double seat, with a footboard 10 in. wide 
raised 6 in. from the ground. Fig. 2 is a double seat 1 ft. 8 in. 
from seat to ground and 2 It. 4 in. wide, with one centre 
back rail. The seat shown at Fig. 1 is 2 ft. 10 in. wide 
and 2 ft. lin. to the ground, and will be found very 
useful, as it enables the shopman to fit boots easily, 
A and B are back rails, and the top raU. A centre 
leg will be necessary under the footboard and seat, and 
cross bearers framed Into the longitudinal rails. The 
footboard may be made movable by framing the rails 
into the legs of the seat and fixing them by means of 
a bolt through each leg, tightened up on the inside 
with a wing nut. 



Double Seats for Shop. 

Strengtb of Beam.— The usual formula for finding the 
strength of a beam when simply supported at both 
ends is— 



W = c 



bd^ 



Where W = breaking weight in cwt. in centre, c = con- 
stant (3'6 spruce fir, I'O Northern pine, Dantzio, and 
Memel, 3'5 Riga, i'S Baltic oak, 5'0 English oak), b = 
breadtn of beam in inches, d = depth of beam in Inches, 
L = clear span or length of beam between supports in 
feet. Where the load is distributed a beam will carry 
double the amount. The safe load for temporary work 
may be one-sixth of the breaking weight, but for per- 
manent work it is better not to exceed one-tenth. 

Cleaning a Plaster Bust. — The best method of 
cleaning a plaster bust when it has got blinded by the 
finer markings getting dulled with dirt, is by careful 
scraping. If the whole figure is simply stained, or 
presents a dirty appearance, the best way Is to give it 
a coat of knotting— a fine varnish that may be bought 
from any house painter— and, when this has become 
thoroughly hard, paint the whole with whitewash, 
adding a little glue to keep it from rubbing oft too 
readily. Whitewash Is preferable to paint for tne reason 



that when the former becomes soiled it is easily removed 
by soaking the bust in water. The water wUl soften the 
whitewash, but leave the varnish underneath intact, 
thus making it possible to retain any delicate modelling 
there may be, and preventing the finer parts from ge£ 
ting filled up as they would be it a succession of poats of 
paint were applied. To attempt to wash the figure would 
only be to further rub in whatever dirt there was on it. 

Making a Scribing Block.— The scribing block shown 
in the accompanying illustrations is made from a rod 
of mild steel 10 in. long and i in. in diameter. This 
is turned down to A in., finished smooth, and quite 
parallel throughout its length. The top is finished 
off as at A (Fig. 1), and the other end, for rather more 
than 1 in., is turned and threaded i in. A collar B is 
then screwed ou tightly. The bottom disc of iron or 




he 



t- 




ii * 

FIG. 4 

How to Make a Scribing Block. 

gunmetal 0, with the bottom dished out, is tapped to 
suit the post. The hole in the sliding block (Fig. 2) 
should be a sliding fit oh the post, the saw cut meeting 
the large hole i this wUl enable the block to grip tlie 
rod and scribingpoint when the nut (Fig. 3) is tightened. 
The steel pin (Fig. i) should be turned, drilled, aiid 
threaded to fit the nut. Two washers (Pig. 5) are 
required, one being grooved diameterwise for the scriDer 
to bed into ; they are planed one at each side of tne 
block (Pig. 2). The ends of the scrlber (Pig. 6) should be 
hardened and tempered. 

Clarifying Dextrine.— A solution of dextrine may bo 
rendered clear by adding to each pint i drachm of alum 
dissolved in J oz. of water ; shake thoroughly, and then 
add i drachm of washing soda dissolved in i oz. of water ; 
again shake, and allow to stand for a few days. The 
hydrate of alumina precipitated out will carry with it 
the suspended matter and some of the colour, leaving 
the liquid much clearer and brighter. 



Cyclopaedia of Mechanics. 



145 



stiffening for Straw Hats. — For stiffening straw 
hats, thin glue size applied warm is generally used. 
Ordinary glue size may be employed for coloured straws, 
and parchment size for white straws. For black straws, 
add a little aniline black to the size to colour it. Spirit 
varnishes may be used for stiffening straw hats ; 
ordinary French polish, diluted with methylated spirit, 
IS also suitable. 

Etching Brass Plates with Acid. — First make a 
pencil drawing on paper of the lettering to be etched ; 
plain block letters will be the best for the purpose. 
Then get a brass plate oi the size required and about Jr in. 
thick, and coat its polished side with white wax or ordin- 
ary beeswax. To do this, heat the plate and rub the 
wax evenly over the surface ; then transfer the lettering 
to the waxed surface of the plate by means of carbon 
paper placed between the plate and the sketch, and 
marked with apeneil. The letters will then appear plainly 
on the plate. Then carefully scrape away the wax inside 
the outline of the letters, care being taken net to remove 
the wax from any part of the plate not to be engraved. A 
wall of wax is then put round the plate to retain the 
acid, which is then poured on the plate and left there 
until it has bitten deeply enough, when it is poured off 
and the plate washed in clean water. The plate should 
then be polished and the letters filled in with black 
japan varnish. 

Simple Curtain Rod.— The accompanying sketches 
show at A an old gas bracket, large enough for a f-in. 
rod as B fitted with curtain rings supporting the curtain. 
The bracket is screwed to the door-post C, and a brass 




Simple Curtain Eod. 

eyelet in the far end of the rod holds a brass chain D so 
that it will bear the weight of the rod, etc., the chain 
being attached to the post about 20 in. above the 
bracket A. Fig. 2 shows a piece of wood which is fastened 
to the wall to act as a stop to the rod. 

Re-covering Cushion with Moquette or Wilton 

Pile.— For a seat 20 in. wide, allow 21 in. for the top, 1 in. 
for the joining seam at the back, 6 in. for the square 
front, and two piped seams, making a total width of 
29 in., providing the seat cover is made out of one piece, 
as is usual with edge seams of cushions made of 
moquette or strips of leather. The heavy pile of the 
cloth prevents a neat appearance. The under lining can 
be made of black glazed linen. Machine up before com- 
mencing to stuff, leaving one corner open to put in the 
stuffing materials. If deep tufts are required, do not 
pack tight. If the front and back are made square the 
cushion will be reversible. Moquette is the French 
name for "Wilton pile. 

Aunt Sally Gallery.- An Aunt Sally gallery should 
be from loft, to 20ft. long and from 10ft. to 12ft, wide, 
" and the apex of the root from 8ft. to 10ft. high, 
sloi)ing from 5 ft. to 6 ft. at the side. The posts or 
uprights, 18 in. of which should go into the ground, 
should be about 3 in. square ; the apex piece for the 
roof should be 4 in. wide and lin. thick, and the frame- 
work for supporting the canvas should be 2 In. square. 
Fasten the woodwork together with smaU carriage bolts. 
The dolls, of which there may be one, two, or three rows, 
should be about 2 ft. high and about 2 in. apart, six or 
eight dolls being placed in each row. The foundation 
for a doll is a stick or piece of wood about 2 in. square 
and 2 ft. long. The head of the doll is made of tow or 
rags tightly wrapped round one end of the stick till it 
forms a ball 4 in. in diameter. The ball is covered with 
calico, the ends of which are tied round the neck of the 
doll; a coat of white oil paint is then applied, after 
which the face is painted in. The body of the doll is 

10 



fashioned from rings of steel wire, the ends of which 
are bedded in the wood. First ring, the neck, 3 in. in 
diameter; second ring, the shoulders, Tin. ; third ring, 
6in.; fourth ring, 5in.; fifth ring, the bust, 4 in. ; sixth 
ring, the hips. Sin. Kings 1 and 2, lin. apart; all the 
other rings 2 in. apart. The rings are connected to each 
other by lacings of finer wire, passing from top to 
bottom, the apace between the lacings being 2 in. in the 
largest ring. The legs are made of calico stuffed with 
tow, and are attached to a piece of wire, 4 in. long, that 
has been driven through the centre of the wood just 
below the sixth ring. A frilled cap is placed on the head, 
and the dolls are otherwise dressed according to taste. 
Hinges are used for fixing the dolls to their perches. 

Coke -breeze Concrete Floor.— In a large area of 
coke-breeze concrete flooring, the coke breeze should 
pass through a sieve of 4-in. mesh, all larger pieces 
being broken smaller, and be retained on a sieve of 
T',i-in. mesh, all the dust that passes through being 
rejected. The proportions should be 24 parts of coke 
breeze, 2 parts of sharp clean sand, and 1 part of 
Portland cement. The whole of the materials should 
be carefully measured, and thoroughly mixed in a dry 
state. The water should afterwards be added slowly 
through a rose nozzle, and the materials turned over 
again at least twice to ensure thorough mixing. 

Fixing Trellis Work The best way to fix a fenca 

of trellis work is to drive stumps (A, Fig. 1) into the 
ground, and to nail on them a top rail B and a bottom 
rail 0. The trellis can then be nailed to the face of 
the stumps and rails. The top rail should be Sin. wide 




Fixing Trellis Work. 

by 2J in. deep, the top being bevelled on to each side 
as shown iu the section (Fig; 2), and a 1-in. by i-ln. 
rebate made on the lace side. The stumps should be 
2i in. square, and must be driven in the ground about 
18 in., the top then being cut off to the right height. 
Each stump must be notched to receive the bottom 
rail, which must also be notched, so that when the 
two are together they will be level or flush on the 
face side. The top rail must be notched the depth of the 
rebate to fit on the top of the stumps, as shown at D D 
(Fig. 1) , and, in fixing it, the rebate must overhang the 
face of the stumps ; this prevents the wet from getting to 
the ends of the laths. The end stumps must be rebated 
in the same way as the top rail, to give a better finish. 

Fitting a Mainspring to a Skeleton Clock.— Take 
the clock to pieces and obtain a spring of the correct 
height and length for the barrel. This should be about 
-,',i in. less in height than the inside of the barrel, and 
when in, its wire should just be capable of slipping 
inside. Ease off the wire tie to the top edge, and slip the 
spring in, taking care that the hole for the hook is in 
such a position that it will slip on the barrel hook. 
When in as far as it wUl go, cut the wire tie and knock 
the spring quite down to the barrel bottom by taking 
the barrel in the hand and striking the bottom heavily 
on the floor or on a wooden bench. If unable to do this, 
hold the spring in a duster to protect the hands, and out 
the wire tie. Then commence at the outside end and 
coil the spring iu a portion of a turn at a time, holding 
it tightly to prevent it slipping out. Rest the barrel on 
a firm stool during the process and hold it with a duster 
lor protection. The operation requires a firm wrist, as 
the spring must not be relaxed in the slightest degree 
until it is aU in. A little bending with pliers when it is 
in will ensure the spring catching on the barrel arbor 
hook in the centre. When in and the cover is on, screw 
the square in a vice and, with the hands, wind it up 
by turning the barrel to the top to see that aU is right. 
Plenty of oil should be applied. 



146 



Cyclopaedia of Mechanics. 



Afflx:n; Gol'l Leaf to Glass. — The only reliable 
medium for afflxing gold leaf to ^lass is weak isinglass 
dissolved in rain-water. The backing should be red lead 
ground in varnish and thinned with turps. Cracking 
and chipping at the edges is due to the use of Bruns- 
wick black, japan, and asphaltum ; these materials are 
nusui.able, beoau.^e cold contracts and heat expands 
them to a very marked degree. 

Cement for Repairing marble.— A simple and ex- 
cellent cement is made by beating the white of an egg 
in flour till the mixture is of the consistency of thin 
paste. This cement will even withstand hot water, and, 
ou account of its colour, is not easily detected. Clear 
shellac or superfine plaster of Paris may also be used. 

Method of Working Mouldings on Arches.— Arches 

of moderate span, say about 6 It., can be worked as 
follows:— Two pieces of timbei'ing should be bolted 
to the caps of the brickwork columns, on which 
another piece is fixed to take the bolt which is in the 
centre of the arch, and holds the radius rod in position 
(see elevation of arch. Pig. 1). A radius rod shotild be 
prepared, to the end of which the templates necessary to 
run the mouldings can be Bxei. The plain part of the 
wall above arches shonld be flanked in with Portland 
cement, this then forming a screed on which the mould 
to work mouldings can travel. A mould should then be 
cut from a piece of wood to the shape of the moulding, 
i in. less being allowed in every part to allow for 
the finishing coat. After this has been used to run 
the moulding in cement, another should then be pre- 
pared to the exact shape and size required, this one 
being faced, as shown in section of arch (Pig. 2), with 
either copper or zinc. The fine stuff is then laid On the 



a grooved seam by folding an edge over on one »a(l 
upon the hatchet stake, and the opposite end, is swaged 
with a hammer swage, which forms a bead of semi- 
circular section along the edge. Half of the bead is 
worked over inside with a round-faced hammer on a 
hatchet stake so as to form a fold, into which the fold 
on the opposite end will fit wheu the body is turned 
round. A flange is next thrown off along the top edge 
with a round-faced hammer on an anvil stake, and this 
flange is worked over towards the outside of the body 
upon a hatchet stake, the size of the flange being pro- 

Sortionate to the size of the wire which it is to cover. 
iraw the fold down over the wire with a mallet, using a 
round-headed stake for the body to rest on, and then 
close the fold down neatly over the wire with the wiring 
machine. With the mallet work round the two ends or 
the top to a radius equal to the top of the body, and 
then Work the body round by pressure from the hands 
upon any convenient tool until it is circular at both 
ends; hook the folds together and draw them together 
closely upoil the saucepan belly stake with a groover. 
Throw off an edge at the bottom with a jenny. Cut out 
the bottom, making it sufficiently large to allow an edge 
to be taken up to flt over that thrown off on the body. 
Planish the bottom by covering the surface with a 
number of blows from a flat planishing hammer upon a 
bright anvil. Next edge up the bottom and pene down 
the edge upon the edge on the body, work the edges 
partly over upon the hatchet stake, and close it down 
smooth and true upon a mandrel. Next rivet on the 
handle, solder round the bottom, along the groove, and 
over the rivet heads to complete the body. II a lip is 




Method of Working mouldings on Arches. 



oement backing, and worked to the required section by 
moving this moiild round the arches by aid of the radius 
rod, as shown. After the moulding has been finished, 
the key block can be moulded and placed in position. 
The intersections of the arch mouldings can all be run 
by having the toil part of the template, from the dotted 
line A upwards, hinged on to the radius rod, so that it can 
be held back while passing over intersecting points. 

Improving Furnace for Melting Lead Ashes.— 

To improve a cube lead-melting furna.ce from which 
the slag comes out with the lead and blocks up the 
hole, the temperature of the furnace should be raised 
gradually and air allowed to enter the furnace to oxidise 
the sulphur contained in the coke. The front of the^ 
furnace should be luted with clay, and a tap hole made 
to remove the slag above the lead. It this cannot readily 
be done, add a shovelful of lime to stiffen the slag. The 
temperature can then be raised and more lime thrown 
In, if necessary, when the slag can be removed in 
lum{)S. A comparatively low temperature is required 
for rich slags and a high temperature for poor slags. 

Making Saucepans. — When making round-bellied 
saucepans, first cut the pattern for a frustum of a right 
cone, usin g the length of the curve of the side as the slant 
for the cone, and the top and bottom diameters of the 
saucepan for the diameters of the ends of the cone. The 
body is hollowed, usually in tacks of four, on a tinman's 
block. Commence by woi-king across from side to side 
on the block until the whole surface has been covered 
and the metal slightly hollowed equally all over. Now 
take the metal over a deeper hole in the block, and work 
along the bottom edge and up to the centre of the body, 
so that the curve of the lower part of the body stands 
out more boldly than the top. Again work over the 
whole of the surface until the metal is smooth. The 
tacks of bodies are then smoothed on a planishing 
wheel, separated, cleaned, and planished singly, either ou 
the planishing wheel or on the anvil. A square notch is 
next cut at both ends of the top, and a corner notch at 
the bottom of the body. The ettds are then prepared for 



required, the wired edge of the body is held firmly on an 
extinguisher stake at the place where the lip is to be 
formed, and a few smart blows are given with the heel of 
a mallet upon the wire at each side of the stake. A lip 
punch is then held firmly on the body from the wire 
downwards, and a blow delivered upon this gives the 
required taper. Oval bodies are the same size at the top 
and bottom, and are usually made in four pieces, the 
seams being formed in the same manner as for the 
round ones, and occurring at the parts of the oval 
where the side curve joins the curve of the end. 
When hollowing, the end pieces are hollowed deeper 
than the sides, and equally at the top and bottom. 
Oval bodies are usually wired after being grooved 
together. 

Warming Buildings by Hot Water.— The custom- 
ary method of calculating the amount of hot-water 
radiating surface required to warm a building is to 
allow so many superficial feet of radiating surface 
per thousand cubic feet of space in each room, hall, 
or corridor. Thus, in living-rooms (a dining-room, 
for instance), it is usual to allow 15 ft. of radiating 
surface per thousand cubic feet of space, and such a 
room measuring 15 ft. by 20 ft. by 12 ft. high-whioh 
would have 3,600 cub. ft. capacity— would need a radiator 
with 54 ft. of surface to it. Entrance halls need 20 ft. per 
1,000, as practically all cold air enters here and should 
receive warmth before going farther. Bath-rooms, 20 ft. 
per 1,000 ; bedrooms, 10 ft. to 12 ft. per 1,000. These figures 
will give an i&e■^. of what will be needed for other 
purposes. They will afford a temperature of about 62 
when there is a hard frost outside. The piping used is 
the "red steam" quality. This is stronger than gas or 
water pipe. Custom has decided that this is the quality 
of pipe to use, but except in very high buildings such a 
thick pipe is not needed as regards its ability to resist 
pressure. Boilers are made of A-ln. and Hn. iron, and 
capable of withstanding any ordinary pressure, but with 
high buildings the saddle boiler or any shape having 
large flat surfaces should be avoided, as the plates may 
bulge out. 



Cyclopaedia of Mechanics. 



147 



Remotlng , zinc from Solder.— To remoye the zinc, 
just melt the solder in a pot, thea take It oft the Are 
and stir in a good handful of powdered sulphur or 
brimstone until the whole is of the consistency of wet 
sand. Replace the pot on the fire and melt, but do not 
stir the contents. The sulphur and zinc will rise to the 
surface and form into a cake. Now takff the pot oft the 
fire and carefully remove the cake without breaking if 
possible. This can be done with two pieces of hoop iron 
with bent ends. 

Design for an Arbour.— Fig. 1 is a plan with dimen- 
sions marked, Pig. 2 a front eleyation, and Fig. 3 a side 
elevation i at Pig. 4 is shown a section through a rail and 
boarding, as at DD (Fig. 3). Fig. 5 shows the construc- 
tion of the joint at A (Fig. 3), Pig. 6 that at B, and Pig. 
7 the group at C. The general dimensions and sizes of 
the principal members are also shown. For the panels 
and roofing, }-ln. prepared matchboarding will be most 
suitable.; the roofing should be covered with felt. The 



is employed, it is either sugar syrup alone or sugar 
syrup to which white of egg has been added. The toys 
made from pure sugar will not melt iu the sun. 

Whlte-enamelltng Furniture. — For white^^narael- 
ling the surface of new wood, the foundation Is built 
up with gilders' washed whiting and patent or parch- 
ment size ; three coats at most should prove sufficient. 
This is smoothed down with worn glasspaper. At 
least four coats of white' euarael should then be 
applied, allowing each coat time to dry before applying 
the next. A superior finish can be obtained by French 
polishing the surface, using transparent polish with or 
without the addition of flake white, as the undercoa,t- 
ing may re9Lnire. If the furniture has previously been 
enamelled, it is not neoessai-y to remove the old enamel 
right down to the wo'od. The surl:ace should be freed 
from grease by thoroughly washing with warm water 
in which a small teacuptul of washing soda has been 
dissolved. A little pumice powder will prove beneficial 




—2.8 
Design for an Arbour. 



sash could either be made fixed or hinged. The arrange- 
ment of the seats is shown in Pig. 1. A simple method of 
fixing the boarding to the framing by means of beads 
at each si,de is shown at Pig. i. 

Making Moulds for Sugar Toys.— First make a 
model of the toy in wax, and take a cast of this in 

glaster of Paris. To do this, procure a small wooden 
ox which will hold the wax model comfortably. Mix 
some plaster of Paris with water -to a very thick 
cream, and pour enough of this into the bo.x to about 
one-third fill it. Next pla,oe the wax model upon the 
plaster with its base pressed against one side of 
the box, and fill' up with more plaster. "When the 
plaster has set, take the box to pieces, remove the wax 
model, and with a fine saw very carefully out the 
mould in half. The cut faces may be smoothed by 
scraping carefully with a knife so that they fit close 
together. The mould may be improved by warming 
and rubbing It with warm paraffin wax or a waxed 
cloth until it has received a slight polish. In using the 
mould, bind the two halves together with rubber bands 
and force the sugar paste or syrup through the opening 
left by the base of the wax model until the mould is quite 
fall. The colours now used are harmless, coal-tar 
(aniline) dyes sold specially for the purpose. If a glaze 



Fio 6 



if the furniture is very dirty. The whiting and size may 
be omitted, and the surface built up with two coats of 
white enamel, as in new work. A suitable enamel can be 
made by mixing finely crushed flake white in transparent 
polish J strain through muslin before use. For a bright 
finish, mix flake white iu best quality white hard varnish. 

Fitting a New Mainspring Barrel to a Watch. 

—In an English lever with fusee and chain, the 
fitting of the barrel is a very simple job, the barrel 
being merely a brass box. Take the rough barrel 
and broach out the bottom hole to fit the bottom 
shoulder of the barrel arbor tightly. Serve the cover 
in the same way. Then turn the inside of the cover 
central boss down until the top shoulder of the barrel 
arbor just appears through. Turn down the inside 
bottom boss until the arbor has just a little end- 
shake in the barrel ; then put in the hook and cut the 
chain hook-hole. F6r the latter, drill two small holes in 
the barrel and broach one slanting into the other. To 
turn the barrel and cover with turns, place them on 
arbors ; with a watch lathe, hold them in step chucks 
and use the slide-rest. For a Geneva barrel with stop- 
work, if possible use the old cover with the stopwork on. 
When finished, ease the arbor in the holes at top and 
bottom. 



148 



Cyclopsedia of Mechanics. 



Finishing Cement Cornices.— A smooth finish is 
obtained by the use of fine Portland cement mixed neat. 
As this works " short," it is left a little time till 
It begins to set ; then fresh water is added, and it Is 
beaten up again. This process brings the cement to 
the state known as " killed," when it sets moi-e 
slowly, attains a less ultimate strength, and works 
easier in the running of the mouldings. If this last coat 
is laid some time after the body of the work has set, it is 
advisable to wet the surface on which it has to be placed 
so that the moisture is not drawn out of the finishing 
coat too quickly. 

Material for Sketching on Glass.— To make the 
material used by sign-writers for outlining letters, etc., 
on glass, melt together i parts of stearic acid, 3 parts of 
mutton suet, and 2 parts of beeswax. Add 6 parts 
of red lead and 1 part of purified carbonate of potassa. 
Mix well together and pour in glass tubes or hollow- 
reeds to set. 

Making a Finder for a Hand Camera.— To make a 
finder for a hand camera, procure a plano-convex or 
bi-convex spectacle lens, unedged or centred, of about 
1-in. focus (cost, 3d.) ; also a piece of zinc and a piece 
of silvered glass. Cut the zinc to the shape shown in 
the figure, and bend on the lines A, B, C, D, B, and P. 
The first two, being bent outwards, enable it to be 
attached to the camera top ; and the last two, bent 
inwards, form a support for the ground glass, which 
rests at an angle of 45°. 'Without knowing the make 
of camera it is intended for, it Is impossible to state 
how the finder should be finished and attached; a 
very common plan, however, is not to make the finder 
complete in itself, but